Jack Fitzgerald

Jack Fitzgerald

Economics PhD Candidate, Vrije Universiteit Amsterdam

Publications

The Need for Equivalence Testing in Economics

Working Paper, 2024

Equivalence testing methods can provide statistically significant evidence that relationships are practically equal to zero. I demonstrate their necessity in a systematic reproduction of estimates defending 135 null claims made in 81 articles from top economics journals. 26-39% of these estimates cannot be significantly bounded beneath benchmark effect sizes. Though prediction platform data reveals that researchers find these equivalence testing ‘failure rates’ to be unacceptable, researchers actually expect unacceptably high failure rates, accurately predicting that failure rates exceed acceptable thresholds by around 23 percentage points. To obtain failure rates that researchers deem acceptable, one must contend that nearly half of published effect sizes in economics are practically equivalent to zero. Because such a claim is ludicrous, Type II error rates are likely quite high throughout economics. This paper provides economists with empirical justification, guidelines, and commands in Stata and R for conducting credible equivalence testing in future research.

Recommended citation: Fitzgerald, J. (2024). "The Need for Equivalence Testing in Economics." Working paper. https://jack-fitzgerald.github.io/files/The_Need_for_Equivalence_Testing_in_Economics.pdf

Is there a foreign language effect on workplace bribery susceptibility? Evidence from a randomized controlled vignette experiment

Accepted, Journal of Business Ethics, 2024

Theory and evidence from the behavioral science literature suggest that the widespread and rising use of lingua francas in the workplace may impact the ethical decision-making of individuals who must use foreign languages at work. We test the impact of foreign language usage on individual susceptibility to bribery in workplace settings using a vignette-based randomized controlled trial in a Dutch student sample. Results suggest that there is not even a small foreign language effect on workplace bribery susceptibility. We combine traditional null hypothesis significance testing with equivalence testing methods novel to the business ethics literature that can provide statistically significant evidence of bounded or null relationships between variables. These tests suggest that the foreign language effect on workplace bribery susceptibility is bounded below even small effect sizes. Post hoc analyses provide evidence suggesting fruitful further routes of experimental research into bribery.

Joint work with Paul Stroet, Arjen van Witteloostuijn, and Kristina S. Weiẞmüller.

Recommended citation: Fitzgerald, J., Stroet, P., van Witteloostuijn, A., & Weiẞmüller, K. S. (Forthcoming). "Is there a foreign language effect on workplace bribery susceptibility? Evidence from a randomized controlled vignette experiment." Journal of Business Ethics. http://jack-fitzgerald.github.io/publications

US states that mandated COVID-19 vaccination see higher, not lower, takeup of COVID-19 boosters and flu vaccines

R&R, PNAS, 2024

Rains and Richards (2024) find that compared to US states that instituted bans on COVID-19 vaccination requirements, states that imposed COVID-19 vaccination mandates exhibit lower adult and child uptake of flu vaccines, and lower uptake of COVID-19 boosters. These differences are generally interpreted causally. However, further inspection reveals that these results arise from poor statistical modelling choices. When corrected, the data instead shows that states which mandated COVID-19 vaccination experience higher COVID-19 booster and flu vaccine takeup than states that banned COVID-19 vaccination requirements.

Recommended citation: Fitzgerald, J. (2024). "US states that mandated COVID-19 vaccination see higher, not lower, takeup of COVID-19 boosters and flu vaccines." Working paper. http://jack-fitzgerald.github.io/publications