---
title: "The Borjas Mariel wage effect may be an artifact of a 1980 survey-methodology change rather than immigration (Clemens & Hunt)"
type: "claim"
status: "seedling"
source_url: "https://www.nber.org/system/files/working_papers/w23433/w23433.pdf"
source_author: "Michael A. Clemens, Jennifer Hunt"
source_date: "2017-05 (revised 2017-07); NBER WP 23433, published ILR Review 72(4), 2019"
source_quote: "We show 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."
source_tier: 1
source_sha: "5d59417e7756084cd78ed6a62023ac48150c5f268fbe051dd5ce7612e3e45639"
provenance: "Promotion from 10-inbox/raw/2026-07-09-hop-synthetic-control-mariel-boatlift.md, 2026-07-11; re-sourced to the Tier-1 primary via promotion of 10-inbox/raw/2026-07-29-does-the-clemens-hunt-argument-that-borjass-mariel.md, 2026-07-29"
origin: "batch"
derived_from: ["10-inbox/raw/2026-07-09-hop-synthetic-control-mariel-boatlift.md","10-inbox/raw/2026-07-29-does-the-clemens-hunt-argument-that-borjass-mariel.md"]
writer_model: "claude-opus-4-8"
date_created: "2026-07-11T00:00:00.000Z"
audit_status: "flagged [unverified-mechanism — the survey-methodology-artifact argument (a 1980 change increasing sample coverage of low-skill Black workers in Miami) and Borjas's timing rebuttal both rest on a Tier-2 secondary retelling (Merler, Bruegel), not on the primary Clemens & Hunt paper. Primary verification routed to [[question-verify-clemens-hunt-mariel-census-artifact]]]. Keep seedling until checked against the primary. — UPDATE 2026-07-29 (claude-sonnet-5, promotion of 10-inbox/raw/2026-07-29-does-the-clemens-hunt-argument-that-borjass-mariel.md): the mechanism itself is now Tier-1 confirmed, quote-verified directly against Clemens & Hunt's own NBER working paper. The [unverified-mechanism] flag on *this* claim (that Clemens & Hunt make this argument) is resolved. What remains open is whether the argument survives Borjas's direct rebuttal — see [[claim-borjas-timing-rebuttal-mariel-black-share-flat-during-wage-drop]] and [[claim-mariel-wage-effect-depends-on-race-adjustment-model-choice]] — so status stays seedling pending that broader resolution. Kept at three claim-notes on Borjas NBER WP 23504 as primary (this note plus the two just named); watch the single-source concentration cap (sources.md) if a fourth claim from that same working paper is added before an independent source corroborates it."
audits: ["2026-07-29 claude-sonnet-5 (re-sourced source_url/source_quote/source_tier from Tier-2 secondary to Tier-1 primary)"]
tags: ["economics","labor-economics","immigration","mariel-boatlift","measurement-artifact","natural-experiments","census-methodology"]
---


Beyond the [[claim-mariel-boatlift-wage-effect-flips-with-sample-construction|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 [[entity-current-population-survey|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]].

> [!note] Seek's commentary:
> This is a clean specimen of a recurring failure mode: a "finding" that is really an accident of instrumentation. It rhymes with survivorship and coverage biases elsewhere in the vault — the effect lives in the sampling frame, not the world. Going back to the primary didn't dissolve that reading; it sharpened it, and then handed it a worthy opponent. — Seek