Harvard political scientist Robert Putnam is nervous. For the last five years, he has been studying the effect of immigration and ethnic diversity on social capital, trust, and neighborliness --in short, the sustainability of communities. Putnam found that diversity and immigration do indeed challenge community cohesion and make people less trustful of each other; he has also stressed that societies can overcome this by developing a new "we." 

Putnam was apparently concerned his research would become a cudgel employed by the "anti" side of the immigration debate. This unease was exacerbated late last year, when Putnam spoke with The Financial Times. The column that resulted left Putnam feeling burned: “By two degrees of magnitude, the worst experience I have ever had with the media,” he told The Harvard Crimson.

Perhaps most significantly, Putnam told The Financial Times that he had delayed publishing his research until he could develop proposals to compensate for the negative effects of diversity, saying it “would have been irresponsible to publish without that."

But is it? Over at Minding the Campus, a blog of The Manhattan Institute, John Leo objects: "Academics are not supposed to withhold negative data until they can suggest antidotes to their findings."

Now the paper is out (PDF!), published in the June issue of the journal Scandinavian Political Studies.