castle                  Data from Cheng and Hoekstra (2013)
df_het                  Simulated data with two treatment groups and
                        heterogenous effects Generated using the
                        following call: 'did2s::gen_data(panel =
                        c(1990, 2020), g1 = 2000, g2 = 2010, g3 = 0,
                        te1 = 2, te2 = 1, te3 = 0, te_m1 = 0.05, te_m2
                        = 0.15, te_m3 = 0)'
df_hom                  Simulated data with two treatment groups and
                        homogenous effects Generated using the
                        following call: 'did2s::gen_data(panel =
                        c(1990, 2020), g1 = 2000, g2 = 2010, g3 = 0,
                        te1 = 2, te2 = 2, te3 = 0, te_m1 = 0, te_m2 =
                        0, te_m3 = 0)'
did2s                   Calculate two-stage difference-in-differences
                        following Gardner (2021)
event_study             Estimate event-study coefficients using TWFE
                        and 5 proposed improvements.
gen_data                Generate TWFE data
