Linear Digressions

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Learning

Speaker(s): Professor Richard H Thaler | Richard Thaler, described by The Spectator as ‘the godfather of behavioural economics’, will be in conversation with LSE Director Craig Calhoun about his book Misbehaving, an authoritative and entertaining history of behavioural economics. Richard Thaler has spent his career studying the radical notion that the central agents in the economy are humans—predictable, error-prone individuals. Traditional economics assumes rational actors. Early in his research, Thaler realized these Spock-like automatons were nothing like real people. Whether buying an alarm clock, selling football tickets, or applying for a mortgage, we all succumb to biases and make decisions that deviate from the standards of rationality assumed by economists. In other words, we misbehave. Dismissed at first by economists as an amusing sideshow, the study of human miscalculations and their effects on markets now drives efforts to make better decisions in our lives, our businesses, and our governments. Coupling recent discoveries in human psychology with a practical understanding of incentives and market behaviour, Thaler enlightens readers about how to make smarter decisions in an increasingly mystifying world, revealing how behavioural economic analysis opens up new ways to look at everything. Laced with antic stories of Thaler’s spirited battles with the bastions of traditional economic thinking, Misbehaving is a singular look into profound human foibles. When economics meets psychology, the implications for individuals, managers, and policy makers are both profound and entertaining. Richard H. Thaler (@R_Thaler) is the Ralph and Dorothy Keller Distinguished Service Professor of Behavioural Science and Economics and the director of the University of Chicago Booth School of Business. He is co-the author of Nudge: Improving Decisions About Health, Wealth and Happiness and has worked in the US with Barack Obama and with David Cameron's 'Nudge Unit' in the UK. Craig Calhoun (@craigjcalhoun) is Director and President of LSE. He is a world-renowned social scientist whose work connects sociology to culture, communication, politics, philosophy and economics. The Behavioural Research Lab (@LSEBehavioural) is a purpose-built facility set up by the Department of Management (@LSEManagement) for the use of researchers examining organisational behaviour and decision making. The BRL’s state-of-the-art facilities include 20 workstations for individual computer-mediated studies and four bespoke discussion rooms with built-in audio-visual equipment for studies in social dynamics. Since its opening in 2011, over 18000 participants have taken part in more than 120 studies.  The BRL caters to researchers across LSE, including Management, Economics, Geography/Grantham Institute, Philosophy, Social Policy, Social Psychology and Government, and offers a large diverse participant pool to its researchers.

Misbehaving: the making of behavioural economics [Audio]

What do you get when you cross a support vector machine with matrix factorization?  You get a factorization machine, and a darn fine algorithm for recommendation engines.

Factorization Machines

In this episode of the Data Show, I spoke with Soumith Chintala, AI research engineer at Facebook. Among his many research projects, Chintala was part of the team behind DCGAN (Deep Convolutional Generative Adversarial Networks), a widely cited paper that introduced a set of neural network architectures for unsupervised learning. Our conversation centered around PyTorch, the successor to the popular Torch scientific computing framework. PyTorch is a relatively new deep learning framework that is fast becoming popular among researchers. Like Chainer, PyTorch supports dynamic computation graphs, a feature that makes it attractive to researchers and engineers who work with text and time-series.

Why AI and Machine Learning Researchers are Beginning to Embrace PyTorch

In this episode of the Data Show, I spoke with Neha Narkhede, co-founder and CTO of Confluent. As I noted in a recent post on “The Age of Machine Learning,” data integration and data enrichment are non-trivial and ongoing challenges for most companies. Getting data ready for analytics—including machine learning—remains an area of focus for most companies. It turns out, “data lakes” have become staging grounds for data; more refinement usually needs to be done before data is ready for analytics. By making it easier to create and productionize data refinement pipelines on both batch and streaming data sources, analysts and data scientists can focus on analytics that can unlock value from data.

The Current State of Apache Kafka

If you've been in data science for more than a year or two, chances are you've noticed changes in the field as it's grown and matured. And if you're newer to the field, you may feel like there's a disconnect between lots of different stories about what data scientists should know, or do, or expect from their job. This week, we cover two thought pieces, one that arose from interviews with 35(!) data scientists speaking about what their jobs actually are (and aren't), and one from the head of data science at AirBnb organizing core data science work into three main specialties.

Relevant links:
https://hbr.org/2018/08/what-data-scientists-really-do-according-to-35-data-scientists
https://www.linkedin.com/pulse/one-data-science-job-doesnt-fit-all-elena-grewal

The Three Types of Data Scientists, and What They Actually Do

If literature, as romantic poet John Keats said, is for soul making, how will our souls be made and remade in a digital age when most reading, if it happens at all, occurs on screens and at light speed? What are the threats to knowledge acquisition, modes of teaching, learning and wisdom?

This Sydney Ideas panel discussion took place on 15 October 2018: https://sydney.edu.au/news-opinion/sydney-ideas/2018/reading-and-writing-slowly-in-a-digital-age.html

Reading and writing slowly in a digital age

The Poisson distribution is a probability distribution function used to for events that happen in time or space. It’s super handy because it’s pretty simple to use and is applicable for tons of things—there are a lot of interesting processes that boil down to “events that happen in time or space.” This episode is a quick introduction to the distribution, and then a focus on two of our favorite applications: using the Poisson distribution to identify supernovas and study army deaths from horse kicks.

Better Know a Distribution: The Poisson Distribution

When you think about it, it’s pretty amazing that we can draw conclusions about huge populations, even the whole world, based on datasets that are comparatively very small (a few thousand, or a few hundred, or even sometimes a few dozen). That’s the power of statistics, though. This episode is kind of a two-for-one but we’re excited about it—first we’ll talk about the Normal or Gaussian distribution, which is maybe the most famous probability distribution function out there, and then turn to the Central Limit Theorem, which is one of the foundational tenets of statistics and the real reason why the Normal distribution is so important.

The Normal Distribution and the Central Limit Theorem

Linear regression is a great tool if you want to make predictions about the mean value that an outcome will have given certain values for the inputs. But what if you want to predict the median? Or the 10th percentile? Or the 90th percentile. You need quantile regression, which is similar to ordinary least squares regression in some ways but with some really interesting twists that make it unique. This week, we’ll go over the concept of quantile regression, and also a bit about how it works and when you might use it.

Relevant links:
https://www.aeaweb.org/articles?id=10.1257/jep.15.4.143
https://eng.uber.com/analyzing-experiment-outcomes/

Quantile Regression

Ordinary least squares (OLS) is often used synonymously with linear regression. If you’re a data scientist, machine learner, or statistician, you bump into it daily. If you haven’t had the opportunity to build up your understanding from the foundations, though, listen up: there are a number of assumptions underlying OLS that you should know and love. They’re interesting, force you to think about data and statistics, and help you know when you’re out of “good” OLS territory and into places where you could run into trouble.

The Assumptions of Ordinary Least Squares

K Nearest Neighbors is an algorithm with secrets. On one hand, the algorithm itself is as straightforward as possible: find the labeled points nearest the point that you need to predict, and make a prediction that’s the average of their answers. On the other hand, what does “nearest” mean when you’re dealing with complex data? How do you decide whether a man and a woman of the same age are “nearer” to each other than two women several years apart? What if you convert all your monetary columns from dollars to cents, your distances from miles to nanometers, your weights from pounds to kilograms? Can your definition of “nearest” hold up under these types of transformations? We’re discussing all this, and more, in this week’s episode.

K Nearest Neighbors

It’s not news that data scientists are expected to be capable in many different areas (writing software, designing experiments, analyzing data, talking to non-technical stakeholders). One thing that has been changing, though, as the field becomes a bit older and more mature, is our ideas about what data scientists should focus on to stay relevant. Should they specialize in a particular area (if so, which one)? Should they instead stay general and work across many different areas? In either case, what are the costs and benefits?

This question has prompted a number of think pieces lately, which are sometimes advocating for specializing, and sometimes pointing out the benefits of generalists. In short, if you’re trying to figure out what to actually do, you might be hearing some conflicting opinions. In this episode, we break apart the arguments both ways, and maybe (hopefully?) reach a little resolution about where to go from here.

The Great Data Science Specialist vs. Generalist Debate

We often hear from folks wondering what advice we can give them as they search for their first job in data science. What does a hiring manager look for? Should someone focus on taking classes online, doing a bootcamp, reading books, something else? How can they stand out in a crowd? 

There’s no single answer, because so much depends on the person asking in the first place, but that doesn’t stop us from giving some perspective. So in this episode we’re sharing that advice out more widely, so hopefully more of you can benefit from it.

Advice to those trying to get a first job in data science

Open source software is ubiquitous throughout data science, and enables the work of nearly every data scientist in some way or another. Open source projects, however, are disproportionately maintained by a small number of individuals, some of whom are institutionally supported, but many of whom do this maintenance on a purely volunteer basis. The health of the data science ecosystem depends on the support of open source projects, on an individual and institutional level.

https://hdsr.mitpress.mit.edu/pub/xsrt4zs2/release/2

The Data Science Open Source Ecosystem

This is a re-release of an episode that originally ran in October 2019.

If you’re trying to manage a project that serves up analytics data for a few very distinct uses, you’d be wise to consider having custom solutions for each use case that are optimized for the needs and constraints of that use cases. You also wouldn’t be YouTube, which found themselves with this problem (gigantic data needs and several very different use cases of what they needed to do with that data) and went a different way: they built one analytics data system to serve them all. Procella, the system they built, is the topic of our episode today: by deconstructing the system, we dig into the four motivating uses of this system, the complexity they had to introduce to service all four uses simultaneously, and the impressive engineering that has to go into building something that “just works.”

Procella: YouTube's super-system for analytics data storage

A few weeks ago, we put out a call for data scientists interested in issues of race and racism, or people studying how those topics can be studied with data science methods, should get in touch to come talk to our audience about their work. This week we’re excited to bring on Todd Hendricks, Bay Area data scientist and a volunteer who reached out to tell us about his studies with the Stanford Open Policing dataset.

A Data Science Take on Open Policing Data

The data science and artificial intelligence community has made amazing strides in the past few years to algorithmically automate portions of the healthcare process. This episode looks at two computer vision algorithms, one that diagnoses diabetic retinopathy and another that classifies liver cancer, and asks the question—are patients now getting better care, and achieving better outcomes, with these algorithms in the mix? The answer isn’t no, exactly, but it’s not a resounding yes, because these algorithms interact with a very complex system (the healthcare system) and other shortcomings of that system are proving hard to automate away. Getting a faster diagnosis from an image might not be an improvement if the image is now harder to capture (because of strict data quality requirements associated with the algorithm that wouldn’t stop a human doing the same job). Likewise, an algorithm getting a prediction mostly correct might not be an overall benefit if it introduces more dramatic failures when the prediction happens to be wrong. For every data scientist whose work is deployed into some kind of product, and is being used to solve real-world problems, these papers underscore how important and difficult it is to consider all the context around those problems.

A Reality Check on AI-Driven Medical Assistants

All good things must come to an end, including this podcast. This is the last episode we plan to release, and it doesn’t cover data science—it’s mostly reminiscing, thanking our wonderful audience (that’s you!), and marveling at how this thing that started out as a side project grew into a huge part of our lives for over 5 years.

It’s been a ride, and a real pleasure and privilege to talk to you each week. Thanks, best wishes, and good night!

—Katie and Ben