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

Episode Summary

Executive Summary: The episode explains how minimum-wage research works, why some studies falsely claim job loss, and why the best empirical evidence finds little to no employment effect while raising wages. Economist Ben Zipperer contrasts flawed studies with stronger natural-experiment methods and introduces newer research showing no total job loss, plus meaningful wage spillovers beyond directly affected workers.

Main Topics: The difference between theory and empirical evidence (Priority: 5/5): The hosts distinguish neoclassical predictions that higher wages should reduce employment from actual studies measuring what happens after minimum-wage increases. How minimum-wage studies are designed (Priority: 5/5): Ben Zipperer explains the natural-experiment approach: compare a treated area with a credible control area before and after a policy change, rather than simply counting jobs after the fact. Why some famous negative studies are flawed (Priority: 5/5): The Seattle study is discussed as an example of poor methodology: weak control groups, reliance on Washington-only data, and single-store data that can misclassify worker movement as job loss. What the best studies find (Priority: 5/5): Across strong studies and the average study since 2000, minimum-wage increases generally show little to no negative employment effect while increasing wages for low-wage workers. New research on broader worker coverage and spillovers (Priority: 4/5): Zipperer describes research using 138 state minimum-wage increases and all low-wage workers, finding no total employment effect and significant wage spillovers above the new minimum. Politics, incentives, and misinformation (Priority: 4/5): The hosts argue that anti-minimum-wage studies are amplified because powerful interests benefit from maintaining low wages, and they offer heuristics for spotting misleading research. Automation and the broader labor market (Priority: 3/5): A voicemail segment addresses the claim that higher wages will accelerate automation, arguing that higher wages raise consumer demand and can support more jobs overall.

Key Arguments: Theoretical models often predict job loss from wage floors, but empirical research does not generally confirm that prediction. Modern minimum-wage analysis relies on treated-vs-control comparisons, not simple before/after job counts. Card and Kruger’s New Jersey–Pennsylvania restaurant study helped establish the natural-experiment method and found no job loss, possibly even employment gains. The Seattle study was influential but methodologically weak because Seattle had no good control group and the data could not separate true losses from workers moving between firms. The study also used only single-store data, which can wrongly interpret shifts from single-location firms to chains as job losses. The average minimum-wage study published since 2000 finds a very small employment effect. Best research shows higher minimum wages raise pay not only for workers directly below the new floor but also for workers somewhat above it. Roughly 40% of the total wage gains from a minimum-wage increase come from spillover/ripple effects. Negative results get amplified because they fit the prior beliefs and financial interests of employers and anti-wage advocates. Raising wages can increase demand, improve consumer spending, and support job growth rather than destroy it.

Data Points: Average employment effect of minimum wage: Really small / essentially zero - Hosts and Zipperer summarize the typical finding from stronger empirical studies and the average study since 2000. Seattle minimum wage studied up to: $13 - The University of Washington study discussed early phases of Seattle's wage hike, before the full $15 target. Seattle phased minimum wage target: $15 and beyond - Seattle's policy was described as ambitious, phased in over several years. Number of state minimum-wage increases in newer study: 138 - Zipperer describes a study using over 130 state-level minimum-wage events across 30–35 years. Share of total wage increase from spillovers: About 40% - The new research finds a sizable portion of wage gains occurs above the minimum through spillover effects. Share of total wage increase from direct floor effects: About 60% - The rest of the wage increase comes from workers directly lifted to the new wage floor. Workers affected by a $15 national minimum wage who are not teenagers: 90% - Used to argue that focusing on teenagers misses most beneficiaries of a higher minimum wage. U.S. federal minimum wage: $7.25 - Referenced as the stagnant national minimum wage during discussion of state and city increases. Seattle restaurant comparison: For every restaurant that closed, three opened - Used to counter claims that Seattle's higher wage destroyed local business activity. Spillover range above minimum: About $1 to $3 above the new minimum wage - Zipperer says wage ripple effects fade but extend into this range.

Pivotal Quotes: "When people see something that says studies show that the minimum wage kills jobs, they shouldn't just take it as gospel." — Nick Hanauer: Opening framing of the episode's skepticism toward headline-driven minimum-wage claims. "What they found doing this experiment ... 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 central result. "A very large portion of the total wages that we see increased because of the minimum wage ... is employers who are not required to raise these people's wages by law, but they do so anyways." — Ben Zipperer: Describing spillover/ripple effects beyond directly covered workers.

Implications: Listeners should treat dramatic job-loss claims skeptically and check methodology, control groups, and peer review. For policy, raising the minimum wage is likely to lift pay broadly with little employment harm, including for workers above the wage floor.