Want to be successful? Know your odds.

If you want to make a difference in your career, you need to think not just about which jobs have the most impact, but in which jobs you’ve got the best chances of success. This point is easy to neglect. It’s all very well working for an incredibly high impact cause, but if you do a rubbish job you won’t make much difference (at worst you might actually do harm).

Judging your chances of success is hard. You probably don’t want to think of yourself as “merely average”. But looking at the average person’s chances is the best place to start if you want to get a realistic picture of how likely you are to succeed.


Formula


The representativeness heuristic

If you’ve ever travelled on the same train or bus route at the same time every morning, you’ll have found you end up seeing the same people every day. When I commuted to work in London from my home in Cambridge over the summer I found myself making up stories about these people to pass the time: imagining what jobs they did and what their lives were like.1 This could get pretty dull, as most of the people in my carriage were middle-aged men; smartly dressed and carrying briefcases, tapping on their smart phones. Bankers, businessmen: boring.

There was one man in particular, though, whose story was different. At first glance, he looked like the rest of them. What sparked my interest was that he read: and not from a Kindle, but from books (shock horror): all with pretty interesting and intellectual-sounding titles. There were some other subtleties: he seemed kinder than the majority of commuters, willing to give up his seat more often, he seemed to take more personal calls, and smiled more. He couldn’t be a cold-hearted businessman.2 I imagined that he instead he worked for a charity or nonprofit, the smart dress being explained by his being in a high up position in one of the more well-established such organisations. This seemed much more likely to me than him just being another businessman.

So imagine my surprise when I was passing through Canary Wharf one evening and I saw this man leaving work from one of the big investment banks. It turned out he was a banker after all. How could I have got it so wrong? He just didn’t seem like the type.

What I’d neglected to consider here, I realised, was just how many suit-wearing investment bankers there are in London compared to CEOs of major charities. Even though this man didn’t seem like a banker, he was still pretty likely to be one: simply because the chances of any suited man commuting to London from Cambridge working in the city are high. By contrast, there are very few high-up positions in big charities, so the chances of any random person holding one of them are very slim, regardless of how altruistic they appear.

Neglecting base rates

It turns out I was making a pretty common mistake called the base rate fallacy. It’s something we often fall prey to when trying to intuitively judge probabilities. Given a description of a person and asked what job we think they do, most people base their judgement on how well the person fits a certain stereotype (known as the representativeness heuristic) rather than thinking how many people there are in each job overall (the base rate.) Even when people are explicitly given base rate information, they often ignore it. This is a well-established bias on which a fair amount of literature has been written.3

This has some serious implications for career choice. If you’re a bright, hardworking and motivated young law student, you might judge your chances of making partner in a big firm as pretty high. You’re exactly the sort of person who would end up making partners, after all.4 70% doesn’t sound completely unreasonable. The problem is that most other law students share these characteristics. And if only one in ten law students eventually make partner in a big law firm (which doesn’t seem unrealistic - in fact, it might be much less, as many won’t even get hired by a big law firm to start with5) then it looks like your judgement is hugely over-optimistic.

We often have a tendency to think of ourselves as better than average. Combined with a tendency to ignore base rates, this means we’re likely to overestimate our chances of success in certain careers. If you want to get a realistic picture of your chances of success, better to start with what normally happens: what the average person’s chances are in your situation. You need to know your odds in order to work out where they are highest. This might sound trivial, but it’s really important and easily neglected.

One way to try to avoid this common error is to think in frequencies rather than probabilities. There’s evidence that people are less likely to neglect base rates when phrased in the form “x number of people out of the total population satisfy y”, than when phrased “the probability of satisfying y is z.” So it might be better to think about how many people are successful in a given field, than thinking in terms of probabilities of success.6

The general point to take away here is that when trying to decide which job to do to have more impact, it’s important to think not only about what causes you are personally well suited to, but also which causes have the highest chance of success regardless of who works on them. You’re probably not going to cure cancer, however well-suited to the task you might seem: simply because the chances of anyone doing so are so low.

However, this doesn’t mean we shouldn’t try to factor in our own skills and talents at all when judging our chances of success. Whilst we don’t want to overestimate our chances, we don’t want to underestimate them either. We’ll be writing more about this soon.


You might also enjoy:

Do you think you’re better than average?

Doing harm when you think you’re doing good: part 1 and part 2

The sunk cost fallacy in career choice


References and notes

Bar-Hillel, Maya (1980). “The base-rate fallacy in probability judgments” Acta Psychologica 44: 211–233.

A related fallacy is confusing necessary and sufficient conditions for success. Being a bright, hardworking, motivated law student may be a necessary condition for making partner, but this doesn’t mean it’s a sufficient one.

  1. Do other people do this too or am I a bit creepy?

  2. Apologies to any business people out there who are offended by this. I know a lot of you aren’t remotely cold-hearted: I’m just playing up to a stereotype for maximum effect here.

  3. Kahneman, Daniel; Amos Tversky (1985). “Evidential impact of base rates”. In Daniel Kahneman, Paul Slovic & Amos Tversky (Eds.). Judgment under uncertainty: Heuristics and biases. pp. 153–160.

  4. The reasoning here seems to go something like: “Most partners in top law firms were bright, hardworking and motivated as law students, I am a bright, hardworking, motivated law student, therefore I have a good chance of making partner in a top law firm.” Putting it like this helps clarify what’s going wrong: this is a slight tweak on reasoning of the form “All A’s are B, I am B, therefore I am A” which is clearly flawed.

  5. A recent article in AM Law Daily discusses the ever-decreasing odds of becoming a big-firm partner, even for Harvard Law graduates.

  6. Gerd Gigerenzer and Ulrich Hoffrage (1995) “How to improve Bayesian reasoning without instruction: Frequency formats”, Psychological Review, 102, 4, 684-704

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