Repost: How to spot a bogus minimum wage study (with Ben Zipperer)

Episode Summary

Executive Summary: The episode explains how minimum wage research works, contrasting weak studies that cherry-pick data with stronger natural-experiment and panel-data approaches. Ben Zipperer argues the best evidence shows raising the minimum wage has little to no effect on overall employment, while boosting wages—including spillover raises for workers above the floor. The hosts also give listeners a practical checklist for spotting bogus minimum wage studies.

Main Topics: How minimum wage studies are actually done (Priority: 5/5): The conversation distinguishes theoretical predictions from empirical research and explains the core methods economists use: treated-vs-control comparisons, natural experiments, quasi-experiments, and panel data across many policy changes. Card-Krueger and the modern empirical turn (Priority: 5/5): The New Jersey vs. Pennsylvania restaurant study is presented as the classic example that challenged the old view that minimum wages reduce employment, helping reshape the field toward better causal inference. Why some studies falsely show job loss (Priority: 5/5): The hosts and Zipperer criticize weak designs that rely on poor control groups, employer surveys, industry anecdotes, unreviewed reports, or selective samples that can manufacture negative findings. Seattle minimum wage study as a cautionary tale (Priority: 5/5): The University of Washington study is described as influential but flawed because Seattle lacked a credible control area and the study’s single-store sample could misread within-city job shifts as job losses. Spillover effects and wage ripple effects (Priority: 4/5): Zipperer’s newer work argues minimum wage hikes lift pay not only for workers below the new floor but also for workers slightly above it, creating substantial ripple effects through the wage distribution. Public narrative, ideology, and policy stakes (Priority: 4/5): The hosts argue that minimum wage claims are shaped by business interests and orthodox economics because the belief that wage hikes kill jobs is politically useful for suppressing wages. Automation and demand effects (Priority: 3/5): In the voicemail segment, the hosts argue higher wages can increase consumer demand and spur hiring, while automation concerns depend on how productivity gains are distributed across workers and owners.

Key Arguments: The best empirical studies of minimum wage increases generally find little to no negative effect on total employment. The classic Card-Krueger natural experiment showed New Jersey’s minimum wage hike did not reduce restaurant employment relative to Pennsylvania. Studies that rely on bad control groups or selective data can produce almost any answer the researcher wants. Seattle’s famous minimum wage study was weakened by the absence of a truly comparable control area and by a sample limited to single-store operations. A large share of low-wage workers are adults, so focusing only on teenagers or restaurants can badly misrepresent the policy’s actual impact. Minimum wage increases create spillover wage gains for workers above the statutory floor, not just those directly targeted by the law. Negative minimum wage findings receive disproportionate attention because they match the ideological preferences of business groups and some economists. Raising wages can increase demand, which can support more employment rather than less, especially when workers spend more of their income. Automation is not an inherent reason to oppose wage floors; the key issue is whether productivity gains are broadly shared or captured only by owners of capital.

Data Points: Typical employment effect in published studies: essentially very small / near zero - Zipperer says the average minimum wage study published since 2000 finds tiny employment effects. Number of state-level minimum wage increases studied: over 130 - Zipperer describes his newer research as analyzing more than 130 minimum wage events over 30–35 years. Share of workers affected who are not teenagers: 90% - In a hypothetical $15 national minimum wage, the hosts note 90% of workers getting raises would be adults, not teenagers. Spillover range above minimum wage: about $1 to $3 above the new minimum wage - Zipperer says wage ripple effects extend to workers earning roughly $1–$3 above the new floor. Share of total wage increase from spillovers: about 40% - Zipperer estimates around 40% of the total wage gain from a minimum wage increase comes from spillover effects. Direct wage-floor effect: about 60% - The remainder of total wage gains comes from directly lifting workers up to the new minimum wage. Seattle minimum wage level mentioned: $15 and beyond - The hosts reference Seattle’s phased-in minimum wage policy reaching at least $15. Earlier Seattle analysis wage level: up to $13 - Zipperer says the University of Washington study examined early stages, with data through roughly $13. National minimum wage: $7.25 - The hosts contrast local higher-wage jurisdictions with the federal minimum wage still at $7.25. Claimed job loss headline: 3.7 million jobs - The hosts cite headlines and CBO-style claims that raising the minimum wage to $15 would cost millions of jobs. Seattle restaurant effect: for every restaurant that closed, three opened - Goldie notes Seattle’s experience showed more restaurant openings than closures after the wage hike. Peer review status of criticized Seattle study: not yet peer-reviewed - The hosts point out the widely cited Seattle study continued to influence debate before peer review.

Pivotal Quotes: "the average employment effect of the minimum wage is actually really small" — Goldie: Opening statement summarizing the episode’s central empirical message. "there really wasn't much of a change of employment. If anything, employment rose in New Jersey after the minimum wage increase compared to Pennsylvania" — Ben Zipperer: Explaining the Card-Krueger natural experiment and its findings. "They don't make these arguments because they're true. They make them because they're the most effective way ever devised to make rich people richer" — Goldie / Nick Hanauer: Commentary on why anti-minimum-wage claims persist politically.

Implications: Listeners should treat minimum wage headlines skeptically and look for study design quality, peer review, and credible control groups. Strong evidence suggests wage floors can raise pay without meaningful job loss, and the debate is often more ideological than empirical.