DataTalks.Club

Running from Complexity

Season 4, episode 5 of the DataTalks.Club podcast with Ben Wilson

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Transcript

Alexey: Today, we'll talk about running from complexity, which means starting with simpler things when we do our machine learning projects. We have a special guest today, Ben Wilson. Ben is a Practice Lead Resident Solutions Architect at Databricks. That's probably the longest title for any guest I had on this show [laughs]. Ben is based in North Carolina and he's been doing data science work for the past 12 years in companies ranging from semiconductor manufacturing to fashion companies. He is working on a book for Manning, titled Machine Learning Engineering in Action, which focuses on how to get machine learning projects into production and help them stay there. Welcome, Ben. (2:14)

Ben: Thanks. Great to be here. (3:02)

Alexey: Yes, it's our pleasure. Before we go into our main topic, let's start with your background. Can you tell us about your career journey so far? (3:06)

Ben’s Background

Ben: Oh, it’s one of the weirdest ones. It's even weirder than my job title right now. It started straight out of high school. I went into the United States Navy and joined a program that involved nuclear engineering – as a technician. I did that for a number of years. I got tired of doing that, so I did a bunch of other things in the Navy, but eventually it exposed me to a position in the last year and a half that I was on active duty. I rose to interim communications officer and dealt with message traffic and computers. It started to fascinate me at just how mindnumbingly boring doing manual tasks on a computer can be. So I started to learn the automation because “I'm so lazy, I want a computer to just kind of do things for me.” (3:14)

Ben: I started to learn scripting and stuff. That catapulted me. Once I got out of the military after almost 12 years of service, I got my first job as a process engineer, which dealt with complex manufacturing processes – running tools and equipment lines, and having to ‘craft recipes’. I got tired of that company and went on to another company, which had me doing a very similar task, but working more in the R&D side of things with emerging products – with a much more complex system. That's where I started to learn even greater tools to maximize my own personal laziness. I started to figure out, “Hey, I hate doing this thing so much. It's really complicated.”

Ben: We had a contract with a company actually here in North Carolina, less than 10 minutes from my house – the SAS Institute. They had all these great training programs and allowed us to use their tooling (for a fee, of course), and I started learning the basics of statistical process control. What we used to call applied statistics, now we call it data science. I started learning all that from those great instructors, and that tooling. This was over a decade ago.

Ben: That started me down a path of working for another series of companies, where I started to do data science work – everything from the largest semiconductor factory in North America to a fashion company, where I learned more intense data science techniques and got exposure to Apache Spark. My current company Databricks, we're a relatively early customer of theirs. I decided to make the journey to learn more about my field and my profession at a company like Databricks. So that long job title is what I call a ‘field nerd’. We help companies build stuff – everything from ETL to traditional statistics, applications, analytics, and truly cutting edge, ridiculous, deep learning, distributed, ML applications. So that's my career journey in a nutshell. I've been doing that for just over three years now.

Alexey: This long title – Practice Lead Resident Solutions Architect – you said it's a ‘field nerd’. (6:40)

Ben: Yeah. (6:49)

Building solutions for customers

Alexey: So basically you help customers build what they need. (6:50)

Ben: Yeah – whatever they need. The topic of today's discussion is highly relevant to that, because that's a narrative that I try to push with teams, particularly when they're just getting into new tooling. People have a penchant for wanting to latch on to complexity, I think. They see the shiny thing in the distance, like “I really want to do that!” Without thinking about what is involved in actually doing it and how complex it could be. So one of the things that we do is work with them and say, “Yeah, that's cool. The shiny thing over there is really fascinating. But let's think about what we're trying to solve here. Let's analyze the process within the frame of vision of who our internal customer is. What problem are they trying to solve?" They just want the problem solved. We're there to help try to solve it. They're not maintaining the code. They're not maintaining the solution – we are. We need to make our lives simpler, which goes back to what I was saying earlier about my own personality of trying to be as lazy as possible. I think laziness is good in data science and engineering work, because it means you can go and do other stuff. Because what you built is easier to maintain. (6:58)

Alexey: You said you help your customers with everything from ETL to traditional statistics, analytics, and this shiny, deep learning, new stuff. I guess when somebody comes to you with a request, “Hey, can you please take this state of the art library or model and train it for us?” You probably start thinking, “Hmm. Maybe you need something simpler.” Is that right? (8:17)

Ben: Or maybe the code that we're looking at is so over-engineered and complex, that the simple solution is, “Hey, let's refactor this to make it more maintainable.” A theme in the book that I wrote, which you mentioned before, is “Walls of text!” I see that very frequently in data science code, which is ‘the god function’. It's a function that is potentially hundreds, if not thousands, of lines of imperative code that is so complicated and hard to follow that the simpler thing is to start breaking it up into smaller pieces in the refactoring process. You can simplify the code. Not just in the sense of, “Yeah, it's easier to maintain.” But there might be dead code in there. There may be code that could be handled in a more efficient, cheaper, and more understandable way. That's something that we do on the professional services side – help customers. (8:49)

Ben: Sometimes we rewrite the code for them. Other times we pair up with them and build it together. The end goal is not just to ‘get something into production’, because that doesn't make successful ML. The end goal is to build something together with a customer – something that they can maintain. We want to build something that is going to be running in production hopefully for years to come – something that they fully understand. Something that they can improve it over time, instead of having this massively complex code base where, if something breaks, or they need to put some new functionality into it, they kind of throw their hands up and say, “I have no idea where to begin with this.”

Why projects don’t make it to production

Alexey: In your opinion, what do you think is the most common reason that projects don't make it into production? (10:35)

Ben: Not making it into production generally comes from one of two things, from what I see. One is – nobody cares about it. There's no business buy-in. You haven't actually paired up with your internal customer to make sure that they're comfortable with what you're building. You haven’t made sure that they've bought into what you're building, and you haven’t demonstrated exactly what this is bringing to the table in terms that they understand – regardless of what the solution is. (10:46)

Ben: The second one is either picking a solution to a problem that’s too complicated to maintain or you can’t even get to the point where you can run it with stability in production. Or maybe it becomes so expensive to run that the return on investment just isn't there. I see that a lot with people that try to apply deep learning to problems that probably don't need it. They say, “Well, to get my model to train, I need X. I have a terabyte of training data.” Okay, that's a lot. “And I need to get my model iterations faster. So I need a GPU cluster on Spark, and I need Horovod to distribute the training – just to be able to get training cycles to work fast enough.”

Ben: Sometimes when you go in and see that – they're focusing on technical issues that they're having, “How do I get this to run faster?” And nobody's taking a step back and saying, “What's the actual problem you're trying to solve? Oh, Churn prediction? Why do you need an LSTM to do that? Here's a Pareto/NBD model that uses Bayesian inference to determine what the probability of somebody churning. By the way, we can run that on your entire terabyte of data in less than five minutes. Let's go that route instead.”

Ben: Sometimes people find themselves at that point mere weeks before they're about to go into production. Or when somebody gets the bill from the cloud vendor, they say, “Why is this Project Costing $100,000 a month to run in training? The use case is not even going to make us $100,000. Turn it off.” That's really demoralizing when a team faces that. Those are the two most common reasons that I see.

Why do people choose overcomplicated solutions?

Alexey: Why do you think that happens? Why do you think somebody wants to run a complex LSTM using a cluster of GPUs on Spark, using Horovod, when they just need Churn prediction? Why do things like this happen? Do you know? (13:19)

Ben: Here's a contentious opinion. This is just my opinion. I think this happens because the people just want to flex – people want to be noticed. All of us are fascinated by technology and that's why we get into this field. We want to do cool stuff. And that stuff is cool – LSTMs, deep learning – they're fascinating implementations. The tech is really complex and cool and it's interesting to use it. However, it's also really hyped up. Everybody's talking about building cool things with those algorithms. But what people don't understand in this field, or they're not focused on this point – it's something that I mentor people about – don't focus on the tech. Don't focus on the tooling. Don't focus on the platform. That's what blogs talk about. You get vendors and creators of open source packages. They're pushing this narrative because they want people to succeed with their tools. But take a step back. I always recommend to people, “Take a step back from what you're doing and just focus on being an engineer. Don't try to be a scientist. Don't go into research mode and try to implement a white paper just because you can or just because you think it's a cool thing to do. Think of applying ML as an engineer would.” (13:40)

Ben: The parallel, or the corollary, that I use when I'm talking about this point is bridge building. If you're talking about building a bridge across a 20 foot gap, a scientist might approach that and say, “Hey, we can construct this bridge out of carbon nanotubes. We can have ultra highway, molecular weight polyethylene wrapping around these carbon nanotubes. We can make a bridge that weighs less than a car and can support a space shuttle.” And maybe it'll work amazingly well. An engineer would never even attempt to do something like that. This is going to be ludicrously expensive and we're gonna have to do all this research to figure out how to even do that. We're gonna have to build the tooling in order to support the construction of the materials to make the bridge out of this stuff. An engineer is going to say, “No, no. Steel is good. We've been building bridges this way for over two centuries.” Some engineers that are more Luddite-type that might say, “No, we can just do concrete and rebar. Let's do that because it works. It's a 20 foot gap. Let's build the minimum required complexity in order to support this. Let's use proven techniques to solve the problem of getting cars from one side of a hill to another side of a hill.” I see that data science works the same way.

Ben: When you're working as a professional in a company – in an ML team, or a data science team – we're there to solve problems. Nobody cares how we solve them. Solving it in proven ways, ways that are consistently proven to work, is the more wise decision. That’s not to say, “Don't play around with the cool new stuff.” Just do that on your own time. That's what a lot of us who have been in the industry do. I'm sure you do it as well, Aleksey. You know, some new cool tech comes out, and you're like, “I'm gonna try that out this Friday evening.” Or “When Saturday morning comes, I'm gonna dedicate three hours and I'm going to play with this new tech.” But generally, you shouldn’t do that sort of thing when you're working on a project for a company. That's a fast ticket to get fired, even if you're experienced.

Alexey: I guess, another problem could be that the person that is tasked with the problem hasn't done this kind of thing before. Maybe they don't have any experience with it, so they start looking it up and then see, “LSTM here. LSTM there. All these transformers. Okay, maybe I'll just go with this.” Then when they need to maintain it, they see that “OK. I’m screwed.” You mentioned a certain method, I don't remember the name of it – the more traditional one, the Bayesian one. I haven't really heard about this, to be honest. When I Google things, I see, “Okay, LSTM and some thing I’ve never heard about. Hmm. Which one do I choose?” So maybe that’s how people end up with these complex solutions. (17:28)

Ben: Exactly. Search engine optimization creates technical debt in data science work. What I always recommend, and what I've always done, is – when I'm working on a new project that I have no experience on, and newsflash to the viewers, even people with 12, 15, 20, 30 years experience in ML, you're still going to run into this constantly. Our industry, our profession, is so broad in the amount of things that you could possibly specialize in. Nobody is going to know it all. I'm not an expert on NLP, but I know people who are. So if I'm working on an NLP project, I'm going to go talk to them. If I'm talking about a customer’s project, I'm going to anonymize it, of course. I'm not going to say, “Hey, I'm working with this customer.” Instead, I'll say, “Here's a problem that I'm trying to solve. Here's the expected outcome. This is what the internal customer wants to see out of this. How would you solve this?” Then I'll ask a couple other people. Maybe I'll assemble a group of experts and turn to the communities that we have, communities that you, Aleksey, have built – and some of those other communities that you listed at the beginning of this – there's amazing talent globally. These people are willing to just come together and help each other out. We all struggle with every bit of this. We all come across the problem of “Where do I even begin?” (18:17)

Ben: If I do a Google search for how to solve a particular problem, I know that the first couple of pages are probably going to be hype. There are gonna be a lot of blog posts that are sponsored by companies that might not be the right solution. Some of the original research is perhaps the best way to solve it and simplest way to solve it – this stuff predates the internet by many decades, if not centuries. Bayesian methodology – this stuff is 19th century, when a lot of the research was done. The original papers that implement this stuff predates computers. So finding those resources that answer, “How would I deal with a nonparametric distribution if I'm trying to estimate this prediction?” This is highly esoteric information and it's really hard to find it when you're just searching on the internet.

Ben: It's much easier to join a community and just ask people that may have done it before. Send out a flare. Some of these communities, everybody's so helpful – somebody will chime in and say, “Oh, I solved that same problem before. Here's what I used.” You'll still get some people that say, “Oh, yeah – use deep learning.” But you might get somebody who's a “been there done that” kind of person – someone who is a little older and more experienced – who will say “No, no, you can solve this with this statistical inference method that's really old, but it's really powerful and fast.” That's how I approach avoiding that trap.

Alexey: That's maybe something I will use as a pitch for the DataTalks.club – your words. (21:31)

Ben: Definitely, you should. (21:36)

The dangers of isolating data science from the business unit

Alexey: The other reason why projects don’t make it into production that you mentioned – nobody cares and there is no buy-in. You also said that we need to focus on being engineers. But I think when we only focus on being engineers, sometimes we get into the trap of “We have this tool. Let's try to find a solution for this tool.” When we're isolated from business units for whom we’re solving this problem in the first place. So how dangerous is it when we become isolated and work on machine learning projects? (21:39)

Ben: Ooh. Siloing of data science is the fastest track to never getting any of your projects actually used in a company. They may be in production and they may be running every hour on the hour. But the chances that people are actually getting value out of that is going to be super low, if you're not involving yourself with the business. I see the modern data scientists as people who are coming from a post grad research position – that is a highly isolated position. You're on your own doing your research. You're using the scientific method to prove a point or to come up with some conclusion of original research. When you come into a business environment from that – it's like night and day. (22:18)

Ben: Some people want to default into what they're comfortable with, which is isolation, or ‘siloing off’. “Hey, I only speak in the terms of data science and mathematics and physics.” But the rest of the business doesn't speak that language. Some of them don't understand that stuff because they don't need to understand it to do their jobs. That's not what drives the company. There are companies that are driven by that, but they're relatively rare.

Ben: An important message that I always have for data scientists coming into the field is – you have to work on your interpersonal skills. You have to get to know people. Know how to build a relationship with people in the business. You don't have to be their best friend, but getting to a point where you can have a frank, open, and honest conversation with the business unit and being able to say, “How can I help you? How can you help me make this better?” That collaboration is super critical for any project. That's where you're going to get all your best ideas anyway.

Ben: A model is going to produce some output, whether it's supervised or unsupervised, deep learning or traditional or statistical – it's going to produce some numeric output. The chances that this numeric output is going to be perfect for the business use case are slim to none. There's usually some post-processing that you need to do – some decision engine that you have to run that prediction through. All the logic of that comes from the business, from the subject matter experts (SMEs). They're the ones that are helping you do your QA, hopefully. They're the ones that are saying, “Hey, data scientist, this is good.” Or, “Hey, this sucks and you need to completely change this.” The earlier and the more frequent that that relationship is built and nurtured and maintained – the more successful every project is going to be.

Ben: You’re customer-focused at that point. You're really thinking about that internal relationship, regardless of who's going to use the solution, having the SMEs involved is going to not only give the project a higher probability of making into production, but it's also going to make the project simpler. It’s because you have to explain what you're building to them – to a layperson. They're like the ultimate rubber duck in that sense. You're explaining through what you're building and they're gonna ask questions, “Well, how does this work?” If you can't explain it to them in terms they can understand, it's probably too complicated. If you can't explain it to the business, it's going to be a nightmare for the next person that comes into the team to maintain that. I always see it as a win-win – the closer that the relationship is between the data science team and the business. The silo walls need to come down if you want to be a successful data science team.

The importance of being able to explain things

Alexey: Why do you need to explain something to the business unit anyway? Why do they even care how this thing works inside? I can say, “Hey, just give us your data, then we do some magic, and you get the output. Trust us – this output is good. You can use it.” So why do we need to care about whether they understand it or not? (26:04)

Ben: They're going to want to understand. If you build that relationship correctly and they're emotionally invested in this project, they're gonna want to know. That is the goal of the data scientist working on it – you’ve got to get them hyped up about it. Humans are naturally curious. If you show them a little peek behind the curtain, they're gonna want to step right through that curtain with you and say, “Hey, I can't speak in your terms, alright? I don't want to hear the nerd talk. But explain it to me like I'm a five year old.” Even though that is kind of an insulting phrase, but explain it to them in terms that mean something to them – in the context of the business and the problem. (26:28)

Ben: They might not understand us when we discuss data science work, but we wouldn't understand how they talk about what they do and their understanding of the business. It's a partnership with people that have expertise in how the company is run, or how finance operates, or how sales operates, or operations. Lean on them, while they lean on you. You need to both jointly understand the project and being able to explain it in a way that you both understand fluently will get you there. That’s going to help ensure that the project is more successful.

Alexey: So basically, if you can explain to them and if they can understand, then maybe they will also have more trust in what you build. Would you agree? (27:45)

Ben: Yes. And they'll come up with ideas, too. Some of the best ideas I've ever had, for any projects throughout my career, have always come from the subject matter experts. It doesn't come from my head. I think of crazy stuff. It might seem like it makes sense – I look at the data, like, “Oh, there's a correlation here between this value and this one!” And then I show that to the business unit and they're like, “What are you talking about? Those have nothing to do with one another.” So I respond, “Oh, so what is important?” And they're like, “Well, you might want to think about X.” – “Oh, I didn't know we collected that data. Let me bring that in. Oh, wow, that just made the model 30% better and it actually solves a problem. And it's simpler. I can do that in SQL!” So yeah, it's super important to be able to do that. (27:55)

Alexey: So basically, we need to involve the subject matter experts as early as possible. Then we need to get the buy-in. We need to make sure that our model is not too complex, so we can safely productionize it in such a way that we can maintain it afterwards – in one year in two years – and so it's not too expensive. Is that right? Then we see the value in it, right? (28:43)

Ben: Right. (29:05)

Maximizing chances of making into production

Alexey: So how do we go about this? Let's say we have some project idea. What does this approach look like? How do we go from the idea to production in such a way that we maximize our chances, that in the end it’ll be in production and have something that is maintainable? (29:06)

Ben: Hm. You said, “_We_ have an idea.” (29:26)

Alexey: Somebody comes to us and says, “Hey, there's this awesome thing. If you do this, our company will make millions.” Or it can come from a data scientist – doesn't matter. We just have an idea. Somebody in the company. (29:30)

Ben: Yeah, I see. I find that it’s different when it's a subject matter expert engaging with the ML team, because they already have the emotional investment. It's their idea. They're going to actively want to work with the data science team. In that relationship, it's on the data scientists to maintain openness – to support that collaborative discussion and include the SMEs in all of the testing and validation that's done. All the way up until production release and even after production release. (29:43)

Ben: But if it's the data science team coming up with the idea, they have to sell that. They have to get that buy-in, and getting that buy-in means – immediately after you do your first rough experiment, you need to timebox these things, as I always say. Say you have this idea, something like, “Oh, if we could only classify cats and dogs better, then our company would make millions of dollars. We need to build a CNN so that we can detect them. We need to test out a Mask-RCNN and we're gonna use TensorFlow and Keras to do that.” Cool. Take two days – take the time out in your schedule to try to build a rough, rough, rough prototype. This could just be some nasty script code in a notebook. Just get something that kind of does what you're thinking of, so that you can produce an output that you could put into a presentation and sell it to the business. Don't spend months working on one of these Skunkworks projects so that you can get it to perfection before you show it to anybody.

Ben: Afterwards, be very open and honest about it and say, “Hey, we only spent 48 hours on this” or “We spent a week on this. It's really rough. But here's our concept.” At that point, you have to go into ‘business selling mode’. You have to say, “Here's what we're proposing. Here's how we're going to do it, we think. We have to do some experimentation, but here's the general idea. Here's what we believe our company is going to get out of this.” After that, I always recommend selling it to the business unit that cares most about that data or to someone who owns the data – owns that business process. Sell it to them first before selling it to executives.

Ben: Because what you don't want to do is have a high level elevator pitch that an executive that will buy into it, thinking that this is going to be a panacea to all the company's woes. Then they talk to the SME team later on and they're like, “What are you guys doing? This is nonsense. This is not going to work.” So talk to the people that know the boots on the ground first. Once they say, “Yeah, this is awesome. We're on board. We’ll totally support this. We'll work with you to make this good.” Then pitch it to the executives. See if you can get a buy-in. You need some sort of executive sponsor, because most ML projects are expensive, not just computationally and in terms of hardware and VMs and stuff in the cloud, but also just time and effort. There are so many other things you could be doing. This one had better be pretty important. (32:03)

Ben: So if they sponsor it and say, “Yes, this is good. This is where we want to go.” Then it constitutes constant involvement of that SME group – from the pre-ideation phase to the planning meetings, where you need to answer, “What do we need built?” “How long do we think this is going to take to do these different phases of this project?” “What are we going to test?” “When's our next meeting?” “When's our presentation cycle?” Once that's all formalized and understood, go off to do two weeks of experimenting, which will go something like, “Hey, we're gonna try out these five different approaches. We're going to split the team up – each sub-team is going to do one of these things. Then we're gonna have a bake-off, internally. And then we're gonna have a bake-off in front of the SMEs.” And they're gonna say, “Oh, we really like number three there. That's super awesome.” And then you present them the cost-benefit analysis of each of the approaches. Like “Okay, number five that we tested – It could be 10 times cheaper than number three, but 1% less accurate.” “What's the trade off there?” “How fast can we get it out?” “How easy is it going to be maintained?” Do that analysis beforehand so that you have that ready for the meeting and then make a group decision.

Ben: I don't ever recommend the data scientists to be the ones that make that decision. We're there to provide the scientific evidence – the results of our experimentation. Let the business decide, “If this is cheaper and faster, we want that.” Alternatively, the business might say “No, we really care about accuracy here. We need you to build this.” Then, you go and build it. But periodically, in ML agile approaches, I always recommend that throughout that development process – after experimentation and the decision is made –each one of those sprints that you conclude, whether it’s two weeks or three weeks, you should have a working version of whatever you're building. Push for that basic MVP at every sprint conclusion, when you cut that feature branch and merge it, master it and run everything and get that artifact, as well as a bunch of demonstrated predictions – that's what’s used as a presentation for the business.

Ben: At a meeting, say, “Here's the status right now, what problems do you see?” And they might say, “Well, you're supposed to be predicting cats and dogs, but we threw a penguin in there and it says that it’s a dog, so there's a problem here.” Show them the results, get their ideas of what to test, and eventually by the time you hit production-readiness level, the model will be good. It'll be good to solve the problem, but it'll also be good because the SMEs have faith in it. They have skin in the game. It's their ideas being shown in code. They're going to want to see it succeed. That's that inclusive aspect with the business that becomes so important, because people are emotional creatures. So when you get somebody who has ownership of a project, even if they're not the one writing the code, they're gonna want to see it succeed. And they're going to be the champions of it when it’s all said and done. They'll use it and they'll help make it better. That's how you make a successful ML. (35:05)

Alexey: SMEs are subject matter experts, right? (36:06)

Ben: Yes, yep. Whoever the geniuses are for that domain. (36:08)

The IKEA effect

Alexey: I heard of this thing called ‘the IKEA effect’, maybe you’ve heard about this as well. (36:13)

Ben: The IKEA effect? (36:19)

Alexey: Yeah. In IKEA, you buy a thing, but it's not assembled yet. You have to assemble it yourself. It's pretty simple – they have an instruction manual for it. Let's say you bought a desk. They include a very simple instruction manual that was tested on many, many people. You just put it together, and then maybe you have this ugly desk when you’re done. But you really love it because you built it yourself. You develop an attachment to this desk. You bought it, and you built it yourself. It's standing there – you can maybe put your laptop on it or eat on top of it. Maybe it's not the same quality as something that somebody could build it for you, but you love it anyway. (36:20)

Ben: Definitely. I think that's a perfect analogy. I think there's a difference with that effect if you're buying a desk and it comes in 10 pieces, versus a desk that comes in 10,000 pieces. You're gonna love the 10 piece desk, no matter how boring and simple it is. It might not be fancy, but it gets the job done. You're gonna love it, because you helped build it. The 10,000 piece desk might be made out of some rare earth metals and might be super fancy, but it costs 10,000 times more than the simple desk. You're still going to be emotionally attached to it, but that's not a healthy attachment. Because you're going to have everything invested in that thing and you're going to be stressed out about how complex it is. When it breaks, you're going to be trying to fix it because you built it. It’s your baby. (37:08)

Ben: The whole company can be in that mindset too. I have seen that effect with certain companies that I've interacted with, where they've built that “10,000 piece desk”. They love it. But they also hate it, because they can't build any more desks. They can't build the chair that goes along with it because they’re too busy fixing the desk over and over and over again. The whole data science team spends 90% of their time just fixing and gluing back on little pieces that keep on falling off.

Alexey: Yeah, I remember I once bought something, not from IKEA, but from another store. It was a German store, so I had high expectations in terms of simplicity – how simple it would be to build the thing. But it wasn't as simple as I imagined. It was much more complex. I hated that thing. I gave up on it. It's still in the basement, not assembled. (38:41)

Ben: Yeah. That can happen with ML as well. (39:13)

Risks of implementing novel algorithms

Alexey: Let's say we have something more complex – maybe a novel algorithm – that we want to try. We heard that right now deep learning is very popular, so we want to try it for our problem. Should we do this? Is this necessary? What kind of risks do we have for doing this? (39:17)

Ben: If you’re going to do that, I'd say use proven deep learning algorithms – if we're talking about CNNs. If you've got an architecture that somebody has spent time building and it’s proven out that it actually works, I'd say it's pretty low risk. That's the benefit of transfer learning. You can say “Alright, I'm going to take Inception v3. I'm going to lock the first 90% of the layers for non-training. Open up the last 10%. Add on my own classifier stage and retrain it on my data.” That’s fairly low risk, because thousands of people are doing that. I've done it dozens of times. It works. Building something from scratch, where you find a white paper and there are novel algorithms in it – that's where the risk comes in. I'm guilty of it myself – of not only implementing those, but also creating them from scratch myself. (39:38)

Alexey: It's fun, right? (40:39)

Ben: It is very fun. But it's important to make sure that there's not a solution already in existence out there that does what you're trying to do. A lot of things that get published, particularly in our field, a lot of people need to publish them, because this is a burgeoning growing field. There's a lot of exciting research being done. There's also a lot of non-repeatable research being done. A lot of stuff that gets published, even if you were to try to re-implement exactly what they did, you can’t – even if they show code, which most of them don't. Sometimes they will have a GitHub repository, like, “Hey, check out the code that I had for my research.” You take that code and you run it on the exact same dataset, but on a different environment, and it doesn't work. It doesn't produce the same results. That's dangerous. (40:40)

Ben: What I usually recommend to people who are thinking of implementing novel algorithms – check to make sure it's possible. See if other people have done it. You don't want to be the guinea pig, unless you've established street cred at your company. What I mean by street cred is – you've already done all the low hanging fruit. You've got dozens of models in production that solve actual real-world business use cases at a company. Say you're working for an e-commerce site. You've got CLV. You've got Churn. You've got fraud prediction. You've got RLV. You've got RFM clustering. You've got recommendation engines. You have targeted messaging for marketing. You’ve got all these models that are currently running and working and doing great.

Ben: Now you're out of the easy stuff. “Oh, I don't know what to do next. The business wants us to do this really crazy thing that I spent two weeks trying to research how other people might tackle this. I've talked to my people over in DataTalks.club. I asked a couple data scientists and asked if anybody tackled this.” And the only response that I got was “Good luck.” Or, “Hey, that's NP-complete. We have no idea how to do that.” If you've gotten to that point, that's when you're going into the white papers zone of saying, “Hey, maybe somebody has done research.” Or “Maybe I can actually contact a university and see if any other postgrad researchers are working on this problem.” That’s when you may try to assume that risk, if you have no other options.

Ben: But the important thing to do there is communicate to the business, and to your management, and probably all the way up to your CTO, of how risky it is. If everybody's on board saying “Yes, this is the direction that we want to go in. Put your research hat on and figure it out.” That's when you're doing novel work. And maybe you should publish your results when you're done. You know, help out somebody else in the future. Because we are that sort of community. But if it's a problem that has been solved by somebody, some way – particularly problems that have been solved by many people over many decades, using what some people might think of as ‘uncool tech’. Like “I don't want to use stats models in Python. I want to use machine learning.” Everything is stats in what we do. So what's wrong with statistical inference? Just learn about it, use it, try it. If it works – great. You just made the business happy. You solved the problem. Now you get to move on to something cool or cooler. That's how I see the implementation of original research.

If it can be done simply – do that first

Alexey: So this is how you earn street cred – by doing uncool stuff first and by not using machine learning. Maybe by using the stats model library before you even moving to Scikit-Learn. Then eventually, you might get into this area where no one has solved this problem before and then you start figuring out how to do it. (44:23)

Ben: Yeah, and even before the stats packages, there's a shocking number of what people would classify as data science work or ML work that you can actually solve in SQL. There are plenty of things like that. Quintile bucketing, windowing operations, building linear equations – things where you can say, “Hey, I just need to interpolate this point between these two other points in order to provide an inference.” It might execute in seconds, versus the ML approach that could take an hour of training and then 10 minutes of validation and all of this code that you have to maintain. Whereas, if you can solve the business use case with simple SQL statements – do that. We're here to solve problems, not to get fancy. (44:47)

Alexey: I think what you mentioned is, you can see how many people have solved this previously, in order to understand how tedious it is. If 1000s of people have done this, like the transfer learning CNN example, then it's low risk. There are tons of resources – maybe you can do this with your eyes closed, because you did this 12 times already. But if it's only 10 people who have done this, and they are the authors of the paper you're reading, then maybe it's a lot more risky, and you should try to solve other, easier problems first. (45:44)

Don’t become the guinea pig for someone’s white paper

Ben: Yeah, and if those 10 people publish something, check to see how many other papers reference that paper. That's always something that I do. I learned that the hard way, several times. “Oh, that's published by this university. They definitely know what they're talking about.” And then you try to implement it or take the actual code and try to run it like, “Wait a minute, there's an issue here with how this works.” Or they did it in a language that you can't transfer easily to another language because of floating point precision or something like that. Then you're like, “Oh, geez. I would have to reimplement how this particular package does its calculation here, so that I could interface with it. So now I have to write my own core mathematical algorithm to support this algorithm that I'm now building on top of that.” It's turtles all the way down when you're in that space. (46:22)

Ben: I sometimes see that in certain customers. Databricks, the company I work for, include the creators of Apache Spark. So distributed computing, people put a lot of large scale ML use cases on Spark because it can support truly ludicrous amounts of data. Not every algorithm is distributable. I've worked with people before who were like, “Hey, we need to do a non-negative matrix factorization on Spark.” Like, “Okay. Well, we have ways of doing matrix inversion in Spark through an iterative process.” And they're like, “No, no. We can't use that. We need to actually invert the matrix all at one time.” Like, “That's gonna shuffle all the data to every other executor. This is gonna be super expensive. And you’re gonna need a massive cluster that can handle this.” And they’re like, “Well, we read a paper.” “Okay, you read a paper on somebody doing this. Let's give it a shot. We'll give it a week. We'll play around with it and try to write some code.” And then later on, you realize that, “Oh, the reason it worked was because the Hadoop cluster that this was running on, that had Spark running on it, had 10,000 nodes available. This company can't afford that amount of VMs to be started in their AWS instance.” So we had to backpedal and say “We can't do this. And here's why.”

Ben: It's important when you’re looking through those papers to read the fine print and then see if other people have been successful in doing it. That's actually what I found a week later – other people referencing that paper saying, “Yeah, this is cool. But this was the environment that they ran this on. So unless you have this amount of horsepower behind you – unless you’re Google – you should maybe not do this.”

Alexey: Yeah, I think I saw something similar. There is a company called Criteo. They actively use Spark. I don't know if they still have their Hadoop cluster. But they liked the fact that they had the largest Hadoop cluster in Europe. So they do a lot of talks about this. But mainly for smaller tech companies, not all these things are as easily implementable. Criteo has this Hadoop cluster and others don't. (49:16)

Alexey: I didn't realize we have so many questions. We have actually six questions.

The importance of stat skills and coding skills

Alexey: Rosona says “My impression is that a lot of companies slip through needing people with basics stat skills. And now I'm throwing data science at it. Do you agree or disagree?” (49:54)

Ben: 100% agree. 100%. I think there are two core critical skill sets that some companies don't realize that they need in order to make successful data science or ML use cases. The first one is statisticians, or rather people with a statistics background. It's such an important aspect of our work. You don't need everybody to have that background. But you need at least one or two people that really understand statistics at an extremely deep level. (50:05)

Ben: The second one is coders. Get a developer to train up the data science team to create ML engineers. I know that that term is thrown around a lot. People are like, “Well ML engineers do ML Ops stuff.” What I mean by ML engineer – my own personal definition – it’s a data scientist who can code. Somebody who can do soup to nuts – you can do the ETL, you can deploy to production, and everything in between. Having a statistics background, as Rosona said, is also super critical as part of that. Even if you're not an expert, you should at least have exposure to that and continuing learning it. Sometimes you might even have to read the old school textbooks that were written far before digital printing was a thing.

Alexey: Yeah, I think I had one of those textbooks. I tried to read it and it was so difficult. (51:31)

Ben: Yeah, some of them are pretty dry and pretty complex, particularly the pure theory ones. The alternative to that is – wait for you (Alexey) to write a book that translates that. There’s a lot of people writing books like that: ”Hey, here's the foundation of this crazy technology, in theory, but let's talk about it from an application standpoint.” And that's really what people needed to know. But having somebody who understands the theories is also helpful. (51:40)

Structuring an agile team for ML work

Alexey: Yeah, thanks. A question from Chetna – “Could you please advise how to structure an Agile Scrum team specifically for machine learning or data science work?” So my experience says that typical software Scrum doesn't fit well to data science. But I think the example you gave was very similar to Scrum in the sense that every two weeks or every end of sprint, you have something that you can show to the stakeholders – to subject matter experts. Every time you finish your sprint, you have a working thing, which is very Scrum-like. (52:14)

Ben: Yeah, and people don't like to hear that. Teams that I've talked to are like, “We can't do that. That's not how we work.” It can be. It's about iterative development in ML. The only way to make that successful – to have that Scrum mentality – follows along with what we've been talking about today. You have to keep it simple. It has to be lightweight. It has to be just barely functional at first. But the Scrum mentality of having buildable, usable, executable code supports you in keeping the complexity down during that development. Because you're simply not going to have enough time. By the way, that's why software developers do that as well. You know that, Aleksey – you come from a software development background. (52:50)

Ben: If you're just left to do whatever you wanted to do, like, “Hey, that project we’re doing… come back in six months, and we'll show you what we've built.” You could build some of the most unmaintainable, crazy code that's so over-engineered. Yeah, it meets the requirements, but it does 10,000 things that they never asked for. So that's why you do that Scrum process of saying, “Just build what you really need in order to hit the target for this sprint.” And you can do that with ML projects, but it involves building very bare-bones, experimental code. This goes into that MVP process, where you're just building on iteratively the new functionality. You might say, “We just want the data to be loaded somewhere. We need to just do some basic feature engineering. Let's get the feature engineering work and run it through this placeholder model.” That placeholder model doesn't have to be an algorithm. It doesn't even have to be ML. It can be an “if-else” statement. It can be a simple linear model that is hand-coded, by taking your feature vector and passing it through just offset weights that you're applying. Keep it as simple as possible.

Ben: Then, once you get the feature engineering all worked out so that you can create a feature vector, maybe the next sprint is “Alright. We know which algorithm we're going to go to with – let's build all that code out – and let's tune all the hyperparameters in an automated way. Let's use UpTuner or Hyperoptic.” That's the sprint. At the end of that, you still have a result. You have predictions that you can show people. The next one might be “Alright, now we're doing unit testing. Let's unit test all that feature engineering code. Let's write all those tests. Let's make sure that we have an integration test from ingest to prediction.” So it's possible. I know it's possible because I've done it many, many times.

Timeboxing research

Alexey: The main concern I hear when somebody says, “Hey, let's use Scrum for research” is that the research is very nondeterministic. You don't know if something you do is going to succeed or not. But I think it's still a good idea to timebox this thing. So you'd rather spend two weeks to conclude that it's not possible, rather than you spend two months or more to conclude that it’s not possible. Right? (55:41)

Ben: Yep. Yeah, I hear that from people all the time. I've gotten that as feedback from the book – the first couple of chapters, like “Well, how can you tell in just three weeks whether something's gonna work or not?” Maybe you can't. Maybe if you spend three years working on the problem, you'll figure it out. You'll get something that's workable and all that good stuff. But as data scientists, companies aren't expecting us to do original research, generally. Some are. But generally, they just want a problem solved. And it's not just the problem that you're working on right now that they want solved. They probably have 100, 200 thousand problems that they want solved. If you're not timeboxing that research and saying, “Hey, we're going to either shelve all of our research for a later date so we can work on something else.” Or we're just going to say, “Hey, we've given it our best shot, and we've tried it out. We can't figure it out. Maybe we need to hire somebody with experience in this field. Maybe we need to have more discussions in the community.” and say, “Hey, how do other people solve this?” That might take time. But if you have that timebox, you can then move over to another project while somebody is taking a couple of hours a week of just continuing that research phase, but not devoting an entire team to trying to figure something out over months. (56:13)

Mentoring

Alexey: There is another question from Rosona about your mentoring. I don't remember if you mentioned something about mentoring today. But – “Is it a formal thing you do or is it something through Databricks?” (57:38)

Ben: I do a number of different things. But for mentoring, we have programs at Databricks. We have several for software development, where we have people in the field that come from a data science or statistics background that are trying to learn how to get better at software development skills. There's a bunch of programs that we do like that, which are formalized meetups and project work. We allow people to learn in the best way that they can, which is learned by breaking it and then fixing it. (57:56)

Ben: We also have programs where we teach ML to people from a data engineering background and a software development background. There's a kickoff that we're doing – we just started the next round this week actually, which is formalized at the end with a capstone project. That capstone project is full end-to-end production ML, which is unit-tested, integration-tested, monitored, with A/B testing built around it. Deployments, CI/CD – everything that you can think about from production ML. That's what we help people build. So they focus on solving a problem with an open source data set.

Ben’s book

Alexey: Thanks. So I know we should be wrapping up. But I also want to ask you about your book. Maybe you can tell us a bit about it and how it’s related to the topic today? (59:13)

Ben: I think everything that we talked about today is covered in the book in some way. And then add another 610 pages on top of that. It's kind of a monster of a book. The first part of the book is talking about process, “How do we think through a problem? How do we have those conversations with a business? How do we do that Scrum implementation from ML?” And it also talks about “What is actually important about solving problems?” and “How do we engage with people to help collectively and collaboratively solve those problems?” (59:27)

Ben: Part two is more focused on implementation of esoteric things that a lot of people don't focus on. It's not the fun, cool stuff. People who really like reading books about “How do I build an algorithm?” That's key, core data science work. You need to know how to build your random forest, or your logistic regression, or how to implement a statistical model. But so many people have written books about that. I wasn't interested in writing that. In fact, what I normally say is, “Hey, go read Aleksey's book on how to do this – if you want to see applications of ML algorithms, and then there’s explanation of how to do that.” I'm focusing more on “How do you automate away the annoying part of that?” Which is “How do you do automated tuning when you have 1000 time series models that you need to predict? How do you automate that? How do you distribute the training and auto tuning of each of those? And then what do you do with them? How do you produce visualizations that are not specifically for data scientists? How do you produce a visualization that tells a story to a business?”

Ben: Then part three is more the development stuff, like “Hey, why is code quality so important? Why is testing so important? Here's how to do this type of stuff. Here's some gotchas that I see.” Because I'm kind of spoiled, being a consultant at a pretty big company. I interact with a lot of companies, so I see how a lot of data scientists do stuff. There are repeated patterns that I see, so I just try to address some of those. “Think about computational and space complexity. This is why it's important. This is why code quality is important. Modularity, abstraction.” If you're not doing these things in your ML code, it's gonna be a nightmare to maintain. That's pretty much the book. It's all the stuff that people usually don't talk about when they talk about ML.

Alexey: You said 600 pages? (1:02:06)

Ben: Yeah, something like that. They're trying to get me to make it go down. (1:02:11)

Alexey: Yeah, I know what you’re talking about. (1:02:14)

Ben: “It’s so expensive to print!” (1:02:19)

Alexey: Do you have a couple more minutes? Because we have three more questions. (1:02:20)

Ben: Sure. (1:02:25)

‘Uncool techniques’ at AI First companies

Alexey: One question from Akshat. “It makes sense to solve problems with uncool techniques. But there are companies who are AI First – they want to show off and say that they have AI capabilities. So what about them?” (1:02:27)

Ben: Good luck. I mean – you're gonna have to spend money for that talent. I'd say less than 5% of companies that I'm aware of, or that I've interacted with, have the budget and the resources to acquire and retain that level of talent. If you're an ‘AI First’ company and all you want to do is the most cutting-edge, most complex implementations of things – that's great, more power to you. I just hope you have the budget for each of those people. You're going to need what they call ‘full stack data scientist’, or what I call an ML engineer. You're going to need people that have been and there done that, and that know how to do those complex implementations or that can build novel algorithms. And they're not cheap. (1:02:45)

Ben: Here in the United States, at least, you could be looking at having to pay somebody half a million dollars a year in salary. Who knows how to do that? Who can successfully do that? Most companies don't have that budget, or they see that price tag, and they're like, “Whoa, wait a minute. That's more than we pay our senior staff developers. No, we're not gonna do that. We're gonna hire people straight out of a Ph.D. program, and then we're just gonna tell them to do this.” Good luck. It's not gonna go well. Those people are probably going to quit because they're going to be under so much stress. They're not going to really know how to do all of that. You need the right talent. You need to bring in the new people, so that they can train, but you need to have processes built around mentoring and cross-training, pair programming. All I can say is “good luck”.

Should managers learn data science?

Alexey: Right, thanks. A comment from anonymous, “I always hear about data scientists having to explain things in simple language to their managers. Do you think it's high time that managers have a crash course on data science?” (1:04:34)

Ben: I think it's important for a data scientist, or rather for any engineer – from a front end software developer all the way to an ML engineer – anybody who's working with tech that is esoteric in nature. You should be able to explain it to your parents, or to your children, or to your spouse… you should be able to explain what you do and how you built something in terms that any human, who has sufficient understanding of business operations, can understand what you're doing. Now, that's not the question that was asked. It's “Should my manager be able to understand terms in what I'm doing?” Yes and no. It's up to the tech lead, I think – whoever the most senior data scientist is – to work with that manager and educate them, and say, “Hey, when we're in our stand-ups and when we're talking about these things, this is what that actually means.” I've done that at companies I've worked for in the past. I don't have to at Databricks because of what we do, and who we hire. (1:04:53)

Ben: But at previous companies – yes. Sometimes the manager doesn't want to ask, or they say, “Hey, I need this explained in simple terms.” It could be because they are afraid to ask what somebody is talking about in a meeting. They don't want to look like they don't know what they're talking about. So the tech lead should be the one telling them like, “Hey, I'm willing to teach you all of this stuff so that you can follow along exactly with what the team is talking about.” They'll probably be grateful. And if they get angry at that, then maybe your company sucks and you need a new job [laughs]. I mean, I would extend the olive branch to that manager and say, “Hey, do you want to learn more about this?” And every single time that I've had that interaction, they're usually so grateful. They're like, “Oh, this is amazing. That's exactly what I was hoping for. Can we meet for an hour after work?” And I’m like, “Yeah, let's create a cheat sheet for you: here's this concept, here's what it actually means in laypersons terms.” People that I've worked with in the past have filled multiple pages front and back with translations like that. That’s their Rosetta Stone to talk ‘data science nerd talk’.

Alexey: I think it's not reasonable to expect from a manager that, if you just send them a course of Andrew Ng or someone else, that they will learn the ins and outs of it. (1:07:17)

Ben: No. (1:07:29)

Alexey: I don't think they will ever do that, because they're busy. They're busy with planning budgets and hiring – a ton of things. They are just too busy to learn machine learning. It's not their core competency. (1:07:29)

Ben: Right. (1:07:48)

Alexey: So it's your job (the data scientist's) to educate them. To tell them “Okay, we mentioned this thing during the stand-up – this is what it actually means.” (1:07:49)

Ben: Yes, right. (1:07:56)

Do data scientists need to specialize to be successful?

Alexey: Okay. Last one. From Chetna “I've often heard people suggesting that to be successful as a data scientist, one should find a niche, for example, become an NLP expert, recommendations expert, etc. What are your thoughts about this?” (1:07:58)

Ben: It depends on what you want to do with your career. Some companies will only ever do one thing. If you're working at an e-commerce site, you'll be exposed to a handful of algorithms that you'll be constantly working with. If you go and work for a social media site, you may have some overlap of those fields of specialization. But there'll be additional ones that will added on top and there'll be some that won't be done at all. If you go work for CERN in the south of France – you're not gonna be using any of that stuff. So there are differences between pure scientific data science work and commercial data science work. It really depends on what you want to do. (1:08:15)

Ben: But what I always recommend is – get really good with the core basics of data science work. What I mean by ‘core basics’ is Bayesian modeling. You don't have to be an expert in it, but know how those things work, why to use them, when to use them. Learn ensembles. When I say ‘learn ensembles’, I don't mean learn how to apply an API – anybody can learn that. I mean learn how a decision tree is built, why it's built that way. What the hyper parameters do. What does it mean that your feature vector has to look like? When you move on to from decision trees, how are random forests made? What does the code actually look like for constructing that? And everybody should know how linear systems work, like generalized linear models. They should understand how they optimize, why they're built the way that they are, and what all those hyper parameters do.

Ben: Once you have that, I think every data scientist should strive to become experts in those three areas within the first two years of their employment. Then they can move into growing that knowledge with advanced statistics of statistical models. Like, “How do time series models work?” You don't have to know all of them. There's dozens and dozens of them. But know a few of them. Then, as you're moving in knowledge from that, that's when specialty usually happens – four or five years in. Alexey, is that about right? After four or five years is when you start to specialize, right? If your company is working on NLP, you may become the NLP guru. If you're working on computer vision problems, you may become really good with Open CV and TensorFlow and Keras with CNNs. That might be your bread and butter, if you want to do that and that's what you're passionate about. Yeah – go all in.

Ben: But when you get to the 10 to 15 year mark as a data scientist, I find most people branch out and try to become a specialist in another field as well. It's just good for career progression to be able to mentor more people, and to be able to contribute more to different problems. It also paves the way to becoming the Chief AI Officer or the Chief ML Officer at companies, which I expect will eventually become more ubiquitous. That's sort of the pinnacle of career growth for people if they want to stay in the field. You have to know how a lot of different things work.

Alexey: And you probably can still be successful as a data scientist without specialization – without a niche. (1:11:42)

Ben: Yeah, generalists work really great. You don't have to have the ability to implement some package from scratch from memory. Having that level of deep understanding of something is not required. Some nerds like myself, can think, “Hey, I want to create a new algorithm that solves this problem where I want to port single node or single machine algorithm to a distributed system.” I just find stuff like that fun, so I do it, if customers have a use case for it. But you don't have to go into that level of specialization. You can be a generalist and say, “Yeah, I know how to build NLP models. I know how to do association roles. I know how to do collaborative filtering. I can implement XGBoost on any problem that you have, and I know how to tune it properly. And I know how to monitor that.” Yeah, generalists can become pretty successful. (1:11:50)

How to find Ben online

Alexey: Okay, thanks. So, let's finish. How can people find you? (1:12:51)

Ben: LinkedIn. I’m also the new co-host to the podcasts on Dev Chat TV – Adventures in Machine Learning. You can hear me ask a bunch of people. You've been on that show, actually. And we're probably gonna have you back. Are you around? (1:12:57)

Alexey: Yes. (1:13:13)

Ben: Yeah, come check me out there. Find me on LinkedIn. And yeah – check out the book if it sounds interesting. It's in early access and I think it's getting published in November – that’s the plan right now. So yeah, you can buy it now. (1:13:14)

Alexey: Okay, cool. Thanks a lot for joining us today and for sharing all your knowledge. And thanks everyone for watching us and asking questions. Do remember that we have three more talks this week. They're all amazing. Check them out if you haven't and register for the remaining events. That's all and thanks again. It was nice chatting with you. (1:13:31)

Ben: Yeah, it was nice for me as well. Thanks, Alexey. (1:13:55)

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