A 2021 paper by Callaway and Sant’Anna proposed a variant of this technique to avoid a problematic “two-way fixed effect” specification for “staggered” designs. The “Ashenfelter dip” raises problems for this technique if it is unknown whether a shock is permanent or transitory. A 2004 paper by Marianne Bertrand et al. that asks “How Much Should We Trust [this technique]” (10[1])simulates inconsistent standard errors using “placebo laws.” A key assumption underlying this technique is the presence of parallel trends (10[1])in the pre-period. (10[3])Card and Krueger (10[1])used this technique (10[1]-5[1])to study the (10[1])effect of an increase in minimum wages (10[1]-5[1])on employment (10[2])in Pennsylvania. For (10[1])10 points, name this (-5[1])causal inference technique that compares the change in an outcome (-5[1])variable over time between treatment (10[1])and control groups. (10[2])■END■ (10[1]0[28])