Isn’t it romantic?

February 11, 2010

Advertising on the London underground seems to follow distinct trends. Several months ago, a huge amount of advertising space was being dedicated to products that could rid your hands of germs, a nice marketing technique when the entire city was paralised with fear over swine flu. In the past month or so, the same advertising spaces have been replaced with a product that’s hoping you want to  get closer to your fellow human beings, not further away: online dating. The diversity in the ads is fantastic: my favourite was a dating site marketed exclusively for South Asians. But the one that caught my eye, and inspired me to write a Valentine’s Day post in its honour, was one for the American website eharmony.

Why did it catch my eye? Because it had an outrageous statistical claim (I am a social scientist, remember): 236  eharmony members get married a day in the US alone. According to company, that comprises 2% of American marriages. That seemed to me incredible. How could one single online dating site possibly account for such a large percentage of total marriages?

So, being the dork that I am, I checked the facts. According to the National Vital Statistics System (run by the Department of Health and Human Services), there were 2,162,000 marriages in the US in 2008. Assuming that eharmony’s stat means, as it seems to apply, 236 eharmony members get married every day, that does indeed work out to 2% of US marriages.

But as I started to do the math, the fact that the statistic was given in terms of the number of people (i.e. members) rather than the number of couples made me realise why the statistic was dodgy.  The statistic actually tells you nothing about what it is you really want to know, which is how many people find true love  using eharmony. All it tells you is that lots of people who are members of eharmony get married. Nothing about whether they marry other eharmony members, or instead whether they signed up to eharmony at 3am on a Saturday night as a drunken dare with their friends and never looked at the site again, and sometime later met the man / woman of their dreams while riding the tube and married them. In fact, given that the first step in the eharmony process (filing in a profile and becoming a member) is free, it’s easy to understand why this number might be exceptionally inflated.

What the statistic does tell you that at some point in their lives, lots of adult Americans are signed up to eharmony (about 2% of the actively marrying population). But whether that’s a good thing or a bad thing depends a bit on whether you think that finding Mrs Right is like finding a needle in the haystack, or a different challenge entirely.