Coincidences appear on every scale

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You have likely heard of the birthday paradox — one of the mathematician’s better-known party tricks which highlights the surprisingly significant probability that some pair of people in a room share the same birthday. In particular, it can be shown that in a room of 23, there’s a 50/50 chance that two of those people will have been born on the same day of the year.

Behind the scenes, this “coincidence” is no more than a statistical phenomenon and it follows perfectly logically from the fact that there are only 365 different possible birthdays — which is actually a rather…

Greater flexibility — or more opportunities to get it wrong?

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A riddle for you.

It’s 2020. I wake up, pour myself a bowl of cornflakes (milk first, cereal second — obviously) and check the news. Then I go out into the garden and lock myself in the shed with a note on the door saying to come and get me when it’s all over. Who am I?

If you answered “literally anyone” then you would probably be correct. However, if you answered “an actuary in charge of modelling and projecting into the future improvements in mortality” then you get extra brownie points. …

This story is about collaboration instead of competition

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In previous articles, we’ve discussed the importance of collaboration between the experts working in different fields of study. Real world problems don’t tend to fall neatly into the scope of one particular area of research — we need to learn to face problems together by not only sharing what we know, but also by being willing to listen — carefully to the ideas of others. We need to remain open enough to admit that we don’t have all the answers and that someone else may have knowledge and perspectives that we don’t.

I think we can all agree that…

A trainee actuary’s perspective

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Human mortality is not a deterministic process (unless you happen to be living in a sci-fi dystopia where remaining lifetime is used as a currency). As such, the estimate of future mortality rates is one of the central assumptions in many pieces of advice that actuaries produce for their clients. An enormous amount of effort is put into incorporating all the latest data into models of human life expectancy and predicting how it will evolve over time as we project into the future.

Although we do have a general understanding of the factors that cause people to live longer or…

Keep your eyes open for these developments in deep learning

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If you’ve ever been to see an opthamologistst, you’ve probably undergone a routine procedure where a specialist takes a picture of the back of your eye.

You will not be surprised to hear that retinal images are rather handy for diagnosing eye diseases. However, you may not have expected that they can also provide a lot of insight into a person’s risk of cardiovascular disease. Retinal imaging is a non-invasive way to examine the condition of someone’s blood vessels, which may be indicative of that person’s wider cardiovascular health.

If you’ve seen one of these retinal images before, you’ll probably…

Why You Should Always Plot Your Data Before Jumping to Conclusions

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Have you ever wondered what statisticians do for fun? You might think that they would enjoy going to casinos and ruining people’s nights by lecturing them about how they’re throwing money away by betting against the odds. Or perhaps you can picture one spending an entire day flipping a coin to hypothesis test whether it’s fair or biased.

But you’d be wrong. In reality, when a statistician is looking for a bit of mild amusement, they spend time finding creative ways to troll people. Check out a prime example below.

Maximise your likelihood of statistical success with this quick and easy guide

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Often, you’ll have some level of intuition — or perhaps concrete evidence — to suggest that a set of observations has been generated by a particular statistical distribution. Similar phenomena to the one you are modelling may have been shown to be explained well by a certain distribution. The setup of the situation or problem you are investigating may naturally suggest a family of distributions to try. …

Precision, Recall, AUC and more — demystified

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It’s 4am and you’re on your seventh coffee. You’ve trawled the forums to find the most sophisticated model you can. You’ve set up your preprocessing pipeline and you’ve picked your hyperparameters. Now, time to evaluate your model’s performance.

You’re shaking with excitement (or it could be the caffeine overdose). This is it — your big debut onto the Kaggle world stage. As your predictions are being submitted, your thoughts turn to what you’re going to do with the prize money. A Lamborghini or a Ferrari? And in what colour? …

Informing the most difficult decisions

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A tiny new human is surrounded by machines and sensors.

A doctor looks on in concern. She knows the odds.


The survival rate for a baby born at 23 weeks.

She puts the thought aside and does what she can.

Inside The NICU

The neonatal intensive care unit (NICU) is an environment in which life-changing decisions are made. Neonatologists use information from a variety of sources to build up a picture of a newborn’s condition to ensure they are receiving the right medical care. …

The lowdown on blogdown

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This article is also available on and LinkedIn.

A personal website is a great place to showcase your work and your achievements. We all know that whether you want to impress at work or whether you want your CV to go to the top of the pile on a recruiter’s desk, you have to be different — you have to be willing go further than everyone else. A sleek, professional-looking website can be one of those things that makes you unique and gives you an edge.

But where to start? You’re a busy person. If you’ve ever taken an…

Andrew Hetherington

Actuary-in-training and data enthusiast based in London, UK.

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