Category archives: Machine Learning

My University Admissions Story And The Pitfalls Of Using Simple Algorithms

Last update on Nov. 11, 2019.


We recently shot a short video describing our company, and it begins with the story of how I originally came to Canada from Ireland. You can watch the video below:


In the video, I explained that I had applied to some Canadian universities, and that the first letter I got was a rejection from McMaster. However, I didn’t get to explain why they rejected me in the video.

I had applied to three universities in Canada: the University of Waterloo, the University of Toronto, and McMaster. Of the three, I viewed McMaster as my fallback choice in case ...

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Why Machine Learning Hasn't Caught On In Finance - A Theory

Last update on Oct. 28, 2019.

Image Credit: eamesBot /


You’d think that machine learning would thrive in finance. After all, the whole industry operates on data. Banks look at your credit history (data!) before they approve your mortgages. Credit card companies look at payment patterns (data!) to sniff out fraud. Investors use financial statements (data!) to select stocks to invest in. 

Anytime there’s an abundance of data, you can often use machine learning to make better decisions, more quickly and with lower costs. You may therefore be surprised to learn not only that machine learning adoption has been slow ...

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The Bias/Variance Trade-off And The Limits of Machine Learning Models

Last update on Sept. 30, 2019.

Image Credit: pathdoc /


A Machine Learning model is a bit like a marriage - no matter how hard you try, it's never going to be perfect. The same way every marriage has its issues, so does every machine learning model. Real world data is like real world people: unpredictable. Real world events don’t conform precisely to a perfectly predictable pattern, so no matter how clever your algorithm, there will always be some irreducible error. The trick is to focus on the things you can change - the reducible error. If you’re in a marriage where there ...

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Outlier Detection: Border Security For Your Model

Last update on Sept. 2, 2019.

Image Credit:  zhu difeng /


You might not know it, but outlier detection is a big part of your life. The ability to notice  diseased or rotten food, or spot a person in a crowd who might be unstable or dangerous is a very important human skill. Many of us had extra detection-training as children

So can we reliably spot outliers? For extreme examples, we're pretty good. Say you ask 100 people, “what is the ideal indoor temperature?” and 99 of them answer, “somewhere between 16 and 22 degrees Celsius”, while the other ...

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Can Yield Curves Predict Stock Market Direction? - A Machine Learning Perspective

Last update on Aug. 19, 2019.

Image Credit: dani3315 /


Many investors are concerned about the yield curve today. Generally speaking, a positive sloping yield curve (i.e. where long term interest rates are higher than short term rates) portends future economic health. By contrast, negative sloping yield curves (a.k.a. “inverted” curves) have tended to precede recessions.

Today, the yield curve is the most inverted it’s been since before the financial crisis. This has led some investors to wonder: should they sell stocks today to protect their portfolios? Or should they hold onto them because, despite widespread belief, yield ...

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The Zeta Coefficient – A New Way to Forecast Returns Using Risk

Last update on July 29, 2019.

Image Credit: Debby Wong /

Risk comes from not knowing what you’re doing

Warren Buffett

As far as superhuman powers go, the ability to accurately forecast returns probably wouldn't be many people's first choice. It's not as sexy as super speed or laser eyes. But, imagine the edge you'd have as an investor if you could look at an opportunity and predict the returns with precision. You would essentially remove all of the risk from investing: you'd be playing the game on easy mode!

Risk and returns are inter-twined. If you can assess risk accurately ...

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Why Decision Trees Work Well For Investment Analysis

Last update on July 22, 2019.

Image Credit: Boo-Tique /


What is the best machine learning algorithm? The answer is, unsurprisingly, “it depends.” There are many different types of machine learning algorithms, each with their own unique way of modelling the real world in some fashion.


Tradeoffs on Model Complexity

The best algorithm is generally one that most closely mirrors the real world. Think of each machine learning algorithm as a set of lego boxes, each containing different shapes of bricks. If you’re going to build an airplane, you’re going to do better with lego boxes containing wing shaped ...

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It's Not Just Hype - Why Machine Learning Holds So Much Promise

Last update on July 8, 2019.

Image Credit: Grigorita Ko /


In the book “MoneyBall”, author Michael Lewis documented the story of the Oakland A’s baseball team. Despite their shoestring budget, the A’s consistently contended with teams with far bigger budgets, such as the New York Yankees. The secret of the team’s success boiled down to one thing - the use of statistics. Instead of relying on the subjective judgements of scouts, the A’s made rational decisions on player acquisitions using data.

Unfortunately, the story doesn’t have a good epilogue. Not long after the book’s publication in 2004, the team’s standing began ...

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My TFSA Update September 2018

Last update on Oct. 22, 2018.

Image Credit: Sarah Holmlund /


In this series, I (Jin Choi) talk about my goal of reaching $1 million in my TFSA account by 2033. If you want to know what a TFSA is, I recommend you read my free book.


September Results: Down 1.2%

At the end of September, I had $56,630 in my TFSA account, which was down by 1.2% since the start of the month. By comparison, the Canadian stock market went down by 0.9% while the U.S. stock market went down by 0.1% in ...

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My TFSA Update August 2017 - Does Combining CNNs and GRUs Yield Better Stock Price Predictions?

Last update on Sept. 18, 2017.

Image Credit: MeskPhotography/


In this series, I (Jin Choi) talk about my goal of reaching $1 million in my TFSA account by 2033. If you want to know what a TFSA is, I recommend you read my free book. In this post, I’ll detail what came of my efforts to combine two machine learning architectures - Convolutional Neural Networks (CNN), and Gated Recurrent Unit (GRU) - in order to make better stock price predictions.


August Results: Down 5.5%

At the end of August, I had $45,907 in my TFSA account, which was down by 5 ...

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