Dear Economist,
I am usually a patient person, but maybe I am overdoing it. I have dated about five different girls, and more or less seriously, but I can’t decide myself. One’s advantages are another’s disadvantages. I know nobody’s perfect – but when should I stop? When can I be sure to have dated enough people to settle down?  – The process of serious dating isn’t exactly cost-free you know…your advice much appreciated!  – An efficient dater.

Dear Efficient Dater,

you are raising a very good question. The answer is, as you probably suspected, there is indeed an optimal number of people to date; a limit after which you can be confident with your choice.  – Economics provides a reason for why there is a limit, and statistics tells you when you have reached it. Let’s start with the economic part.

It was George Stigler, who, as far back as 1961, made a case for limiting one’s search. (He thought more about searching the optimal household appliance, but his reasoning holds just as well for dating..) Stigler says, any market has a given range of quality. We don’t manage to expand that range by searching more, we just get to know it better. In other words, the more you search, the closer you are to having tested the entire available quality range. This also means, with every additional person that you meet and date, your additional knowledge gain diminishes.

At the same time, the effort, time and money spent on an additional date do not diminish. So you are likely to have ‘spanned’ the quality range after a limited number of dates, after which additionals only cost time and money, but do not provide quality gains. Rational daters will settle after reaching this number.

So, where is that number, on average? The answer is twelve.  Knowing twelve people should be enough to know the quality range available in the dating market.  Peter Todd from the Max Planck Institute for Psychological Research did the odds (in his paper ‘Searching for the next best mate’, ebda 1997). Following Todd’s ‘fast and frugal algorithm’, if you date twelve people and then choose the one further person that tops the list, you have a 75% chance of getting it right.

So, bottom line, dear Efficient Dater, you are not there yet. You need to hold out for another 7. If you are honest and stay out of the bases there’s nothing wrong with checking them out in parallel. Might be less costly, too.

Good luck, Your Economist