37 PERCENT RULE — Why knowing this rule will give you exclusive power and ultimate satisfaction?

  • How many people should you date before deciding to ‘settle down’ and get married?
  • How many interviewees should we look at before deciding on “The One”?
  • How many flats should I look upon before saying “Yes” to one of the offers?
  • How many hotels should I look before deciding on the one to settle into?
  • How many internships should you do before deciding on a job offer?
  • How many careers should you try out before you figure out which your favourite is?
  • Spend too long probing your options and you fall prey to analysis paralysis and let promising opportunities go by. (Overly Exploratory)
  • Close out the process too quickly and you risk regretting options you never considered. (Overly Exploitative)
37 percent rule
37 percent rule


The 37 percent rule comes from ‘optimal stopping’ theory in mathematics, which determines the optimal time to take a particular action in order to maximize reward and minimize cost (aka, the best time to stop seeking more options and pull the trigger). According to mathematicians, that point is right after you’ve seen or explored the first 37% of your options.

TECHNICAL (1/e Stopping Rule)

This oddly precise recommendation actually has a formula behind it and mathematicians insist this rule gives you the highest probability of making the optimum choice. If you’re into math, it’s actually 1/e (1 over e, where ‘e’ is the basis of the natural logarithm), which comes out to 0.368, or 36.8 percent or 37% as the number of choices increases.

Image copied from Wikipedia

PSYCHOLOGICAL TEST on Exploit or Explore Conundrum

Mathematics provides the best solution to the “optimal halting problem.” But there’s just one big issue with it: Humans are not rational probability-crunching machines. In fact, the opposite is usually true. We’re beautifully, infuriatingly, creatively, and messily chaotic. So, it falls on psychology to tell us about how we actually behave.

  • If you are visiting a city, you know vaguely well, will you go to a restaurant you know is nice, or will you try somewhere new?
  • If I tell you a gambling machine has a payout of $50, will you stay and play or explore to see if others have a bigger payout?
  • When you’re playing a game, do you tend to stick to the same tactics or mix it up each time?



A historical problem that derived this rule called “Secretary problem” at around 1960.

Secretary problem
Secretary problem
Secretary problem — sample selection
Secretary problem — sample selection


So, let’s think over it for some time, what essentially the solution says is that if you have a consideration set of around 10 girls before you decide which one to marry, you should not commit to anyone, until you have looked through at least 4 of them. Post which you should be ready to commit to anyone who is better than all previous ones.


In his book “Algorithms to Live By: The Computer Science of Human Decisions”, Brian Christian applies the 37% rule to assist Macy in finding the ideal apartment to rent. In his words: “Assuming you want the highest odds of acquiring the best apartment, spend 37% of your apartment search, or the first third (eleven days, if you’ve allotted yourself a month for the search), noncommittally examining choices. You’re just calibrating; leave the checkbook at home. But following that, be ready to immediately commit — deposit included — to the first location you find that surpasses all you’ve already viewed. This is more than just a naturally satisfying middle ground between looking and leaping. It is the demonstrably best course of action.


Following this rule will save you from getting unnecessarily mired in information gathering and data analysis, get you into action, and maximize your probability of success.

  • When trying to pick the best among many options, how many samples should you try before you commit? This is known as the optimal stopping problem.
  • Mathematicians advise us to eliminate the top 37% of any possibilities in order to increase the likelihood of the best result.
  • People typically “explore” or “exploit” more, depending on the psychology. Unfortunately, relationships are messier than probability would suggest.

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Quantum Thinker

Quantum Thinker


I write about Notions built from 3Ms : Maxim, Mental Model & Metaphor related to Finance — Health — Philosophy — Psychology — Technology. www.quantumthinker.io