According to Professors Eli Finkel and Benjamin Karney, as reported in the New York Times, “For a fee, many dating sites will collect data about you, crunch the numbers and match you with someone who, as eHarmony puts it, has been ‘prescreened for deep compatibility with you across 29 dimensions.’ Sites like Chemistry, PerfectMatch and GenePartner make similar scientific-sounding claims. But can a mathematical formula really identify pairs of singles who are especially likely to have a successful romantic relationship? It’s hard to be certain, since the sites have not disclosed their algorithms. But — as we and our co-authors argue in an article to be published this month in the journal Psychological Science in the Public Interest — the past 80 years of scientific research about what makes people romantically compatible suggests that such sites are unlikely to do what they claim to do. One major problem is that these sites fail to collect a lot of crucial information. The sites have no way of knowing how two people will interact once they have been matched. Yet our review of the literature reveals that aspects of relationships that emerge only after two people meet and get to know each other — things like communication patterns, problem-solving tendencies and sexual compatibility — are crucial for predicting the success or failure of relationships.