They say that three times is a trend, so I will have to make do with two thirds of a trend regarding Nicholas Kristof's use of social science research. Or more precisely, regarding Kristof's use of research to back what he presents as inconvenient truths regarding the behavior of poor people or the efficacy of attempts to help them.
Instance 1: Kristof is currently taking a lot of heat from liberal social policy experts for using anecdotal evidence to suggest that significant numbers of parents of children receiving Supplemental Security Income (SSI) deliberately keep their children illiterate to avoid losing the child's disability check. More precisely, Kristof uses anecdotal evidence supported by statistical sleight-of-hand.
Harold Polllack rather gently points to the questionable deployment of data. I'd like to elaborate a bit. Pollack's case first: