[WIP] Add efficient DiD estimator (Chen, Sant'Anna & Xie 2025)

.Rbuildignore

@@ -22,3 +22,18 @@ Icon?
 ^\.lintr$
 ^revdep_manual$
 ^vignettes/.*_cache$
+^benchmark$
+^CSX2026\.pdf$
+^Efficient_DiD\.pdf$
+^Rplots\.pdf$
+^CODEX_AUDIT_HANDOFF\.md$
+^EDID_implemention\.md$
+^IMPLEMENTATION_PLAN\.md$
+^METHODOLOGY_REVIEW\.md$
+^audit\.md$
+^audit_cov\.md$
+^comprehension\.md$
+^implementation\.md$
+^mailbox\.md$
+^spec\.md$
+^test-spec\.md$

.gitignore

@@ -13,8 +13,26 @@ desktop.ini
 /Meta/
 did.Rproj
 ..Rcheck/
+*.Rcheck/
+*.tar.gz
 .claude/
 CLAUDE.md
 .vscode/
 .revdep_manual/
-vignettes/*_cache/
+vignettes/*_cache/
+
+# Personal working files (not part of the package)
+CSX2026.pdf
+Efficient_DiD.pdf
+Rplots.pdf
+CODEX_AUDIT_HANDOFF.md
+EDID_implemention.md
+IMPLEMENTATION_PLAN.md
+METHODOLOGY_REVIEW.md
+audit.md
+audit_cov.md
+comprehension.md
+implementation.md
+mailbox.md
+spec.md
+test-spec.md

NAMESPACE

@@ -1,29 +1,38 @@
 # Generated by roxygen2: do not edit by hand
 
+S3method(as.data.frame,edid_fit)
+S3method(coef,edid_fit)
 S3method(ggdid,AGGTEobj)
 S3method(ggdid,MP)
 S3method(glance,AGGTEobj)
 S3method(glance,MP)
 S3method(nobs,AGGTEobj)
 S3method(nobs,MP)
 S3method(print,AGGTEobj)
+S3method(print,AGGTEobj_edid)
 S3method(print,MP)
+S3method(print,edid_fit)
 S3method(summary,AGGTEobj)
+S3method(summary,AGGTEobj_edid)
 S3method(summary,MP)
 S3method(summary,MP.TEST)
+S3method(summary,edid_fit)
 S3method(tidy,AGGTEobj)
 S3method(tidy,MP)
+S3method(vcov,edid_fit)
 export(AGGTEobj)
 export(DIDparams)
 export(MP)
 export(MP.TEST)
 export(aggte)
+export(aggte_edid)
 export(att_gt)
 export(build_sim_dataset)
 export(compute.aggte)
 export(compute.att_gt)
 export(compute.att_gt2)
 export(conditional_did_pretest)
+export(edid)
 export(ggdid)
 export(glance)
 export(gplot)
@@ -59,6 +68,7 @@ importFrom(generics,tidy)
 importFrom(methods,as)
 importFrom(methods,is)
 importFrom(stats,aggregate)
+importFrom(stats,as.formula)
 importFrom(stats,binomial)
 importFrom(stats,complete.cases)
 importFrom(stats,cov)
@@ -74,6 +84,7 @@ importFrom(stats,predict)
 importFrom(stats,qnorm)
 importFrom(stats,quantile)
 importFrom(stats,rnorm)
+importFrom(stats,sd)
 importFrom(stats,setNames)
 importFrom(stats,var)
 importFrom(tidyr,gather)

NEWS.md

@@ -1,5 +1,7 @@
 # did 2.3.1.904
 
+  * Added `edid()`: efficient DiD estimator (Chen, Sant'Anna & Xie 2025) supporting PT-All and PT-Post parallel trends assumptions, analytical EIF-based standard errors (iid and cluster-robust), multiplier bootstrap inference (Rademacher, Mammen, Webb), and overall/event-study/group aggregation with WIF correction.
+
   * Fixed bug where `faster_mode = TRUE` and `faster_mode = FALSE` produced different ATT estimates when sampling weights (`weightsname`) vary across time. The fast path was always using first-period weights; it now correctly uses the same period's weights as the slow path
 
   * New `fix_weights` argument in `att_gt()` gives users explicit control over how time-varying sampling weights are resolved in each 2x2 DiD comparison. Options: `NULL` (default, preserves existing behavior), `"varying"` (per-observation weights using RC estimators), `"base_period"` (fix at g-1 for all cells), `"first_period"` (fix at first period). See `?att_gt` for details