The Borjas Mariel wage effect may be an artifact of a 1980 survey-methodology change rather than immigration (Clemens & Hunt)

Beyond the sample-construction dispute over the Mariel Boatlift, a separate objection argues that the disputed wage drop may not reflect the labor market at all. Michael Clemens and Jennifer Hunt argue, in their own words, that "conflicting findings on the effects of the Mariel Boatlift can be explained by a large difference in the pre- and post-Boatlift racial composition in subsamples of the Current Population Survey extracts. This compositional change is specific to Miami, unrelated to the Boatlift, and arises from selecting small subsamples of workers." They report the Black share of Borjas's Miami subsample "roughly tripled" between the 1979 and 1985 surveys, driven partly by a nationwide, boatlift-unrelated push to improve Census Bureau coverage of low-skill Black men ahead of the 1980 census. Because that subgroup had lower average wages, a composition change in who was measured — not a real change in what anyone was paid — could by itself produce the low-skill wage decline Borjas attributed to the refugee inflow. Adjusting for the Black share, Clemens and Hunt report results "similar to those of Card (1990)... little to no wage impact of the Mariel Boatlift is discernible."

This is the capture's sharpest twist: mechanism arguing with mechanism, two layers down from the original policy question. The first layer is whether immigration lowered wages; the second is whether the measurement of wages shifted in a way that mimics the first. Borjas has contested this on timing grounds — see claim-borjas-timing-rebuttal-mariel-black-share-flat-during-wage-drop — and the exchange continues from there into a dispute over which race-adjustment model is correct — see claim-mariel-wage-effect-depends-on-race-adjustment-model-choice.