When should you finally pick a life partner? Economics has an answer!!

By: Dr. SirisakChueykamhang


  • You can use simple criteria to find the optimal point, when it is not too early and not too late to end your search for a mate and finally settle down.
  • To increase the chance of finding the best girlfriend or boyfriend, just apply some simple math to the problem. Start by figuring out the number of people you will have time to date during your search. Next, go on dates with 37% of that number of people. Then it's time to get serious, as you carefully compare each new person you date to all the previous ones, and finally settle down with the next person you meet who is better than all the previous ones.

Are you still single? Are you always wondering when will you finally meet the right one? We all want to find our soul mate, right? I can hear the words from that old song ringing in my head, "Stop in the Name of Love". We think that love will finally bring a stop to this search, but maybe it's better if logic told us when to stop. I have a friend who married the first girl he ever dated, and I always wonder how he could have known that she was the best one for him. And then there is another friend of mine I call a “serial dater”, who has been dating one girl after another for the last ten years with no end in sight. I think the important thing for everyone is to not choose too early or too late. To reach this optimal point, you just need to pick the best person at the best time according to simple logic. People who choose too soon or too late often end up with an unsuitable life partner.

If we look at this from a purely economic point of view, finding the optimal point to stop the search involves tradeoffs between time and opportunity costs. The search costs us time, and the longer we search the more likely it becomes that we will pass over the best opportunity. This is why it is of great importance to end the search as soon as possible, however, we are always getting romantic advice from others to calm down, have patience and that our soul mate will eventually find us. But if we move from emotional thought to rational thought, then it is clear we need of settle down with someone soon because waiting a long time only decreases the chances of meeting our best life-partner.

This question of when to stop searching has been studied by expert mathematicians for over 50 years as "The Secretary Problem". It is essentially the same problem, but an employer is interviewing secretaries instead of potential mates. The employer needs to fill the secretary job position under these three conditions: 1) each candidate must be ranked by how suitable they are for the job compared to the previously interviewed candidates; 2) only one candidate can be interviewed at a time; 3) a yes or no decision for each candidate must be made immediately after each interview with no chance to change the decision later. The mathematicians looked for a solution to this problem by first breaking it down into a "search period" and a “decision period". During the search period the candidates are ranked, but none of these are hired. Then, during the decision period, the candidates continue to be ranked until one is found that is better than any that came before, and this is the person who is hired as the new secretary.

Let's imagine a situation where there are three secretarial candidates. If the employer interviewed all the candidates, the ordered ranking would have six possible outcomes: 1-2-3, 1-3-2, 2-1-3, 2-3-1, 3-1-2 and 3-2-1. Following the mathematicians' recommendation, the employer will interview the first candidate during the searching period, and thus not choose them. Then, the employer will be left with two more candidates to choose from, but they will have to hire the second one if that candidate is better than the first, or the third if the second is worse than the first. There are two sets of possible outcomes: 1) 2-1-3, 2-3-1 or 3-1-2 where 33% of the time the worst secretary is hired, due partially to the small number of candidates; 2) 1-2-3 and 1-3-2 where the first candidate is the best but missed because they were interviewed during the searching period, and 3-2-1 where the employer would choose the second candidate without considering the third, which was actually the best. By choosing too fast, the best candidate is missed 16% of the time. Hence, the technique of always passing on candidates during the searching period provides a better than random chance of choosing the best candidate. If the number of candidates is increased to one hundred, then we can find the best person by using the mathematical law of 37% for the searching period. Please look at the references for the proof and calculations, which equal 1/e where the chance of choosing the right person, "e" is the mathematical constant 2.71828, and 1/e is 0.3678794, or about 37%. Compare this to random chance, which is about 1/100 or only 1%.

To increase your chances of finding the best life partner using math and logic, start by setting the target group or the number of people that you have time to date during your search. Then, after dating 37% of those people, it's time to get serious and pick the next one who is better than the others. The 37% rule refers to the point in your search where it is best to change from the searching period to the decision period. Other research from Michael Trick, looked at a typical person's dating life between the ages of 18 and 40 years old. When the 37% rule was applied, it showed that the age of 26.1 years old is the optimal point in life to change from the searching period to the decision period. And what if the object of our affection refuses us? Then, the mathematicians recommend that we decrease the searching period from 37% to 25%, and keep trying till you meet the right one.

The 37% rule can be applied to other situations to help determine the best time to stop searching for something. But for any of you readers over 26 years old, it's time to make that decision now, otherwise you may never find the one who would be your best partner in life.


  • Ferguson, T. S. (1989). Who solved the secretary problem?. Statistical science, 4(3), 282-289.
  • Smith, M. H. (1975). A secretary problem with uncertain employment. Journal of applied probability, 12(3), 620-624.
  • Trick, M. (2011, February 27). Finding Love Optimally [Blog Post]. Retrieved from https://mat.tepper.cmu.edu/blog/index.php/2011/02/27/finding-love-optimally/