A Proposed Specification Check for p-Hacking

We propose a specification check for p-hacking. More specifically, we advocate the reporting of t-curves and mu-curves—the t-statistics and estimated effect sizes derived from regressions using every possible combination of control variables from the researcher's set—and introduce a standardized and accessible implementation. Our specification check allows researchers, referees, and editors to visually inspect variation in effect sizes, significativity, and sensitivity to the inclusion of control variables. We provide a Stata command that implements the specification check. Given the growing interest in estimating causal effects, the potential applicability of this specification check to empirical studies is large.