---
title: "The measured wage effect of the Mariel Boatlift flips with sample construction — no effect (Card) versus a 10–30% drop for dropouts (Borjas)"
type: "claim"
status: "seedling"
source_url: "https://www.bruegel.org/blog-post/mariel-boatlift-controversy"
source_title: "The Mariel Boatlift Controversy"
source_author: "Silvia Merler"
source_date: "2017-06-05T00:00:00.000Z"
source_quote: "very drastic"
source_tier: 2
provenance: "Promotion from 10-inbox/raw/2026-07-09-hop-synthetic-control-mariel-boatlift.md, 2026-07-11"
origin: "batch"
derived_from: "10-inbox/raw/2026-07-09-hop-synthetic-control-mariel-boatlift.md"
writer_model: "claude-opus-4-8"
date_created: "2026-07-11T00:00:00.000Z"
audit_status: "flagged [unverified-quant — the load-bearing figures (Card: no effect; Borjas: 10–30% dropout wage drop; Peri & Yasenov: 15–20 Miami observations per year) rest on a Tier-2 secondary retelling (Merler, Bruegel), not on the primary papers. Only the fragment 'very drastic' is preserved as a verbatim quote. Primary verification (Card 1990 ILRR, Borjas 2017 ILRR, Peri & Yasenov synthetic-control paper) is routed to [[question-verify-mariel-boatlift-wage-effect-primary-sources]]]. Keep seedling until the numbers are checked against primaries."
tags: ["economics","labor-economics","immigration","mariel-boatlift","natural-experiments","synthetic-control"]
---


The 1980 Mariel Boatlift — roughly 125,000 Cuban refugees arriving in Miami over months — is the canonical natural experiment on how a sudden low-skill labor supply shock affects native wages. Serious economists working the same government data have reached flatly opposite headline conclusions, and the divergence tracks sample-construction choices rather than the event itself.

David Card's 1990 study found no measurable effect on less-skilled Miami wages. George Borjas (2015/2017) restricted the sample to high-school dropouts and reported a wage drop on the order of 10–30% for that subgroup. Giovanni Peri and Vasil Yasenov rebutted Borjas using the [[claim-synthetic-control-built-to-measure-basque-terrorism-gdp-cost|synthetic control method]] — built originally for Basque conflict economics — to construct a comparison "Miami," and argued that Borjas's result depended on "very drastic" sample restrictions, leaving only 15–20 Miami observations per year.

The structure recurs elsewhere in the vault: it is the same move as [[claim-soviet-emigre-career-premium-was-structural-not-ability]], where holding ability constant and varying arrival year reverses a talent story into a market-structure story. Here one holds the event (the boatlift) constant and varies the *comparison-group construction*, and the sign of the conclusion flips. A separate line of attack argues the whole effect may be a measurement artifact rather than a real labor-market response — see [[claim-mariel-wage-effect-may-be-1980-census-methodology-artifact]]. Card's Mariel work later anchored his [[claim-card-2021-nobel-natural-experiments-labour-economics|2021 Nobel]].

> [!note] Seek's commentary:
> "Hold the event constant, vary the estimator" is the transferable template — a warning that a natural experiment's headline number is often an artifact of researcher degrees of freedom in defining the treated and control samples. — Seek