DataTalks.Club

Machine Learning Design Patterns

by Valliappa Lakshmanan, Sara Robinson, Michael Munn

The book of the week from 08 Feb 2021 to 12 Feb 2021

The design patterns in this book capture best practices and solutions to recurring problems in machine learning. The authors, three Google engineers, catalog proven methods to help data scientists tackle common problems throughout the ML process. These design patterns codify the experience of hundreds of experts into straightforward, approachable advice.

In this book, you will find detailed explanations of 30 patterns for data and problem representation, operationalization, repeatability, reproducibility, flexibility, explainability, and fairness. Each pattern includes a description of the problem, a variety of potential solutions, and recommendations for choosing the best technique for your situation.

Questions and Answers

Denis Lepchev

Hi Mike Munn - thank you and your colleagues for such a great book!
I have a question regarding the “continued model evaluation” design pattern. As you mention in the book, usually we act on the model’s predictions - as an example trying to prevent customer’s churn.
How companies like Google deal with the feedback loops, when acting on the model’s prediction changes the outcome, making it impossible to observe the ground truth? Many books and articles mention this problem, but the solution is not discussed.
One of the solutions I am aware of is to have a small (untouched) hold-out group as a basis for model evaluation and for re-training, but it comes with its own set of problems. Is there an alternative method(s)?

Mike Munn

Hi Denis Lepchev thanks!
You bring up a really good point about ‘feedback loops’ when dealing with continued model evaluation. There is a lot written about this. I remember reading an article about a company called Stripe that discussed this problem for them in some detail for a credit fraud model they had developed.
We discuss this briefly in the subsection called “Capturing ground truth” as well as other considerations. You mention a good approach. Another technique to consider is to use causal impact models. Causal impact uses Bayesian techniques to understand how a certain “treatment” might have affected a population. It’s commonly used in scenarios where it’s not possible (or not ethical) to have a hold out or control group. This is commonly used at Google and that team has open sourced a CausalImpact package you might want to check out.

Denis Lepchev

Thank you for the answer, Mike.

Alper Demirel

Hello Mike Munn, thank you for writing this beautiful book and coming to this channel 👏

  • What is the most important difference from similar books on the market?
  • Why did you need to write such a book with your friends?
Mike Munn

Thanks so much Alper Demirel. I’m glad you enjoy it. 🙂

  • In my mind, this book would come after an intro book or reference on ML. We certainly talk about how you would do things (and there is a github repo with code implementing the ideas in code) but this book is focused more on common problems and their solutions that we’ve learned in working with customers along the years. Likely a lot of patterns will be familiar to you, if you’re a practicing ML/AI engineer. So this book is a kind of formal collection of “notes from the field” and solutions to common real world problems of building and productionizing ML models.
  • Following on a bit from my point above, another reason we wanted to write this book (in addition to having a collection of common problems/solutions) was to create a shared language for these ML patterns. Like any pattern, you find yourself using the same tricks over and over. And in talking with other colleagues we wanted to create a single term or phrase that describes that problem/solution. So, for example, the “Bridged Schema” pattern gives a name to the common problem that arises when dealing with changing data fields. This way, we can try to have a shared language of common patterns for everyone to use.
Alper Demirel

Thank you so much for the answers, now I’m more excited to read the book 🤩🔝

Aleix

Hi there, Mike Munn! Pleasure talking to you :)
What has been the most recurring problem to an ML engineer like you when working at Google?

Mike Munn

Thanks Aleix glad to have the opportunity to talk to you as well. 🙂
That’s a good question. It’s hard to say what the most common problem would be. I work a lot with Google Cloud customers. We typically work on engagements that span the entire ML work lifecycle. The project specific problems or patterns that arise are so use case dependent. So I guess the most recurring problems then would be the problems that relate to initial or final stages of the lifecycle (since they are broad and similar across multiple use cases). Those would be the patterns addressing data issues or dealing with Responsible AI and working with business stakeholders. Typically the most common problem is in framing the problem and understanding issues with the data. That seems to be consistent across all projects I’ve worked on.

Matthew Emerick

Hey, Mike Munn! Appreciate a moment of your time. Your book is on my (rather large) Amazon wishlist. I do have a question for you. Are the patterns organized by difficulty level?

Mike Munn

hi Matthew Emerick! Happy to be able to stop by 🙂 I know too well about large book to-read lists lol.
The patterns aren’t arranged by difficulty. Instead we arranged them loosely with the different stages of a typical ML workflow or ML lifecycle. So we start with patterns related to Data Representation, then move to Problem Representation, then talk about patterns related to Resiliency and then Reproducibility and end with Responsible AI and stakeholder management.

Matthew Emerick

I like that. Is there anything about the complexity (ie bubble sort is easy to do, but slow) for each pattern?

Mike Munn

kind of! Each pattern is broken down into four main sections: Problem, Solution, Why It Works and Tradeoffs & Alternatives. The Tradeoffs & Alternatives section discusses exactly that. We touch on any ‘gotchas’ or complexity issues, or common pitfalls or just other related approaches you might want to consider.

Matthew Emerick

Okay, so the expected style for a pattern book. Makes it easier anyone who has used a pattern book in the past. Good plan. Organization is something I touch on in my book reviews, both macro and micro. A well written book with great and important content can hit a wall if it’s not organized well. Great job!

George Melvin

Hey Mike Munn, thanks for sharing your time with this community! I’m excited to dive deeper into the book. My question is around company size: are certain patterns more conducive to smaller/larger teams/organisations? In particular, I’d be interested to hear about your experience (re)learning patterns when moving between teams/organisations that are comprised of larger/smaller teams. Thanks!

Mike Munn

hi George Melvin thanks for having me
Good question. The patterns are more focused on implementation. So I can see how they would apply to both smaller/larger orgs. That being said, for some smaller orgs or smaller teams there is less focus on some MLOps aspects. For example, we have a section on Feature Stores. This is a super useful pattern and important to know about; however, I can image for a smaller org the need for a feature store may be less imperative than for a large organization where you have dedicated teams to engineer features for the models that another dedicated team is building.
But, I’d say the patterns in general are relevant for small or large teams and orgs. Just some may resonate more than others.

George Melvin

Great, thanks for your answer! I ’m looking forward to learning more 🤓

Neal Fultz

Thanks Mike Munn for answering questions. Mine is: what are the most dangerous anti-patterns that you have encountered?

Mike Munn

Hi Neal Fultz and thanks!
Ohhh that’s a good one. A lot of things come to mind. I think the most dangerous (and I may be biased in the type of work I usually do and some bad past experiences) would be anti-patterns related to reproducibility and resiliency. So much of ML development is experimentation (with data, with pipelines with models, etc) and reproducibility is crucial to running thorough experiments. Also, as I work with more companies interested in productionizing their models, anti-patterns related to resiliency really end up being more and more detrimental

Mike Munn

hello Everyone. Thanks for having me visit the channel and the opportunity to talk about the book 🙂

Dr Abdulrahman

Thank you Mike Munn for the book and for your time answering questions.
I have three questions:

  1. From your experience, how would you assess the awareness of these patterns among senior practitioners. Would you say the majourity of seniors are not aware.
Mike Munn

hi Dr Abdulrahman very happy to join the channel this week.

  1. I’d imagine that for most senior ML practitioners would be aware of the majority (if not all) of these patterns. Though they might not know it by the name we used. We have code for each pattern and use a variety of tools, some of them more recently developed than others. So even senior practitioners might be able to learn something new from the book.
  2. That’s a good question. I’m not sure. I imagine it would likely come from constraints either in their infrastructure or project timing. For example, someone may understand the importance and need for Continued Model Evaluation but it can be difficult to implement carefully and require too much overhead for the business objective.
  3. I wouldn’t say a complement book is needed, but it could certainly help. This book touches on patterns across the entire ML lifecycle so a book more focused on one aspect (say data engineering or ML pipelines) could be helpful for more implementation details.
Dr Abdulrahman

Second question: What drives many seniors not to follow these patterns when developing their ML models?

Dr Abdulrahman

Third one: Would we need a complement book about data engineering (pipeline) design patterns.

Simon Steinkamp

Thank you Mike Munn for taking the time answering questions here 🙂
The idea of design patterns is actually very new to me and it was very interesting to have a quick look at those. Having heard the term “copy-paste” data scientist recently, I have the feeling that some patterns probably evolve naturally, especially through worked examples for tensorflow, keras or scikit-learn.
Knowing that your book goes beyond the model fitting step, I was wondering what your opinion on these patterns is?

Mike Munn

Hi Simon Steinkamp thanks for joining with questions 🙂 I’m not familiar with the term “copy-paste” data scientist, but I think I can guess what it’s referring to. In some sense, the ideas are similar. However, these design patterns are more like ways of thinking when designing solutions or building ML systems. This book would follow a course on how to effectively build ML model, so we don’t get into the weeds about those details. There are already really great books out there that address that. The idea of patterns is more focused on ways of thinking and recognizing common solutions to common problems. The solutions can’t typically be copy-pasted directly (since each case is a bit different) but the idea is certainly repeated.

Simon Steinkamp

Great, thank you for your answer, I will have a closer look 🙂

Poornima

Hi Mike Munn first of all congratulations on your book release which will help so many ML practitioners on their professional and/or learning journey.
Like to ask two questions:

  • What was your motivation behind coming up with the idea of writing a book on design patterns in ML.
Mike Munn

hi Poornima Thank you! I hope you enjoy it.

  1. The motivation came from lots of customer engagements at Google Cloud in our roles. When designing ML systems or thinking about common ML approaches, we saw that there were some common patterns in the field. The book attempts to collect those pattens into a single easy to reference source.
  2. There wasn’t any monolithic use case or project but we did try to use similar datasets throughout the book when illustrating a concept. This way, the code solutions would be less about the data or model and more about the pattern itself.
Poornima

Thank you much Mike Munn for answering. Looking forward to gain great knowledge from the book. Hoping to see more such excellent works from you in future. All the very best 🙂

Poornima
  • Is there any sort of monolithic usecase/project you are illustrating to showcase the optimal design patterns for each stage of ML lifecycle for that particular case.
    Thank you.
Poornima

Thank you much Mike Munn for answering. Looking forward to gain great knowledge from the book. Hoping to see more such excellent works from you in future. All the very best 🙂

Alexey Grigorev

I remember when I was learning design patterns (the GOF ones), I tried to use them everywhere, and in most cases, it was doing more harm than good. With experience, I learned when the patterns should be used and when they shouldn’t.
Do you think something like that can also happen with ML design patterns? If yes, what advice would you give to beginners to get started with ML design patterns?

Mike Munn

Alexey Grigorev yeah for sure! It’s like the typical hammer/nail scenario. For beginners, I think it would be helpful to first just read through the patterns to be aware of what’s out there. Then revisit certain patterns based on the individual use case and really question of it will help solve the problem you have. The final chapter of the book gives an overview of all the patterns, breaking them down in a simple chart of problem/solution/description. If you think a pattern might be a good solution, take a critical look at the section that discusses that one in detail. And see if it fits or not.

Alexey Grigorev

Makes sense, thanks!

Justin Neumann

Dear Mike Munn,
I read parts of your book with my O’Reilly learning account and I really liked it so far! I particularly like the idea of the “Reframing” concept. Do you think it is applicable to a single, global (gradient boosted tree) regression model that captures multiple time series (which is the problem I deal with on a daily basis)? I can’t think of a way to apply the “target binning” regression -> classification approach to such a global model, unfortunately.
Thanks in advance for the answer!
PS: I have the book on O’Reilly, so no need to give me a book 😉

Best, Justin

Mike Munn

Thanks Justin Neumann great question. The Reframing pattern is an interesting one. It’s focus is less on the model itself and more on how the labels are represented. So, for example, the regression -> classification reframing discusses how you can modify a typical regression problem and frame the problem as learning a probability distribution via classification and binning. One scenario where it is useful is when there may be training examples which have the same features but different labels (I think in the book we used the dataset of birthweights). This way you are learning a probability distribution for a feature input and it can be less confusing for the model. So you’re really just changing your labels, and you would modify your gradient boosted tree to be classification instead of regression. The pattern isn’t model dependent. Does that make sense?
One last point to mention is that this approach of reframing may just not be beneficial to your data or use case. As with most solutions, it’s very use case dependent.
Lastly, I’m glad to hear you have the book. I really hope you enjoy it!

Justin Neumann

Thanks for the reply. Your answer makes all sense to me and you’re right, this pattern may just be not applicable to my problem. I’ll keep reading! 😉 Best, Justin

Rosona

Hi Mike Munn! Thanks for taking questions. Who do you see as the perfect reader (slash ideal audience) of this book? Do you see it as essential even for the raw beginners, or something to ingest after e.g. a year of experience or more?

Mike Munn

Hi Rosona Thanks for joining in. Our target audience was someone that knows the basics of ML and building models. We kind of pitched it as a follow up to a beginning ML book, like Geron’s book “Hands On ML with SciKit and TF” or Muller/Guido’s book “Intro to ML with python” or after a semester course in ML. With more experience, I image the reader would be able to appreciate (or recognize) more of the patterns.

Alexey Grigorev

How would you rank patterns in terms of applicability and usefulness for applied machine learning in industrial settings?
Which patterns come first to mind and we should use them in most of the projects?

Mike Munn

Alexey Grigorev yeah good question. When I think about applied machine learning or ML projects we’ve done with our cloud customers, I think the most useful and common patterns are those that show up in our chapters on Repeatability and Resiliency, patterns like ML Pipelines, Continued Model Evaluation, Batch Serving, Keyed Predictions, Batch Predictions, Feature Store, Transform, and Model Versioning. Also, the Responsible AI patterns are also really important for applied machine learning projects.

Alexey Grigorev

Thank you! And what is the least used one? You mentioned feature stores as something that smaller teams/companies usually don’t need - maybe this one? or some other one?

Mike Munn

yeah some of the patterns are more use case driven, so I’ve personally see those less. And yes, patterns like Feature Store seem to be much more important for industrial teams. In my experience, smaller, more agile teams might not benefit or need to have a feature store set up. They can be incredibly useful and necessary for some situations, but can also require a lot of technical overhead.

Alexey Grigorev

Got it, thank you!

Rishabh Bhargava

Hi Mike Munn - thanks for writing this book! So invaluable as we figure out good practices for shipping ML systems. My question is: what were some design patterns (if any) that you would have liked to include, but that had to get edited out? 🙂

Mike Munn

Hi Rishabh Bhargava thanks for joining with questions. It’s funny, that question has come up before, and honestly I think we were able to catch all the patterns we had in mind. Our initial list didn’t come out to such a round number of 30, but as we were writing a couple topics we thought would be covered as one pattern ended up getting their own section, or the opposite (some individual patterns ended up getting grouped together naturally). So in the end, we covered the ones we wanted….though, now that it’s been put in my mind I’m already thinking of new patterns we could have added 🙂

Rishabh Bhargava

I have a 2 parter question as a follow up.

  1. Do you think these design patterns will need significant updates in the near future, or these patterns represent some general truths about how ML systems should be built?
  2. If you think updates are likely, do you think the second edition will be needed in 6 months, 1 year, 5 years or 10 years?
Mike Munn

yeah good questions,

  1. i don’t think these patterns themselves will need much updates..though, for some, the code or implementations could change over time and be updated or improved as tools continue to develop as solutions to address these common problems
  2. I don’t foresee the need for an second edition soon, but if code updates do become necessary, they’ll make it into the book’s github with the code examples much sooner.

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