EventStudy

• **A1 -- RollingWindowModel now restricts each rolling window to COMPLETE PAIRS** (both firm and index finite) before computing x_bar/ss_xx/ residuals/sigma. Previously, rows where the firm return was NA but the index was not still contributed to x_bar/ss_xx, biasing beta whenever NA-firm rows co-occur with index outliers. fit() and calculate_statistics() now share the same complete-pair count for df/FEC.
• **A2 -- A fully-degenerate event (zero finite event-window abnormal returns) is now EXCLUDED from every CAR-based multi-event statistic** (CSectTTest, PatellZTest, SignTest, GeneralizedSignTest, BMPTest, KolariPynnonenTest), applied once per group (at most one warning per group, not one per configured statistic). Previously it was coalesced to 0 and silently understated cross-event dispersion. The pre-existing STATS-03 convention (a partial gap contributes 0 to that event's own CAR) is unchanged.
• **A3 -- KolariPynnonenTest never falls back to an adjustment factor of 1.** A degenerate (constant or too-short) estimation-window SAR series is now excluded from the r_bar cross-sectional correlation estimate (reported once); if fewer than 2 usable events remain, kp_t/ckp_t are NA instead of silently reporting the unadjusted BMP value. The per-day KP adjustment now uses THAT DAY's n_valid_events instead of the first day's count applied uniformly to every day.
• **A4 -- RankTest and GeneralizedSignTest now group by event_id, not firm_symbol,** for ranking/centering and p_hat estimation. Previously a firm recurring across multiple events had its data silently pooled across those events.
• **A5 -- cross_sectional_regression() sample-integrity hardening.** Duplicated event_ids in the data argument now error; a car_window extending outside any event's available event window now errors; task events with no matching data row are dropped with one warning; an event whose CAR is NA because an abnormal return inside car_window is missing is excluded with one warning (.extract_cars() no longer sums with na.rm = TRUE, so ANY missing AR in the window makes the whole CAR NA; car_by_group()/car_quantiles()/plot_car_distribution() inherit this NA-CAR semantics without an additional warning).
• **A6 -- OLS insufficient-observations guard is now n_params-based, not a flat threshold,** for MarketModel and every LinearFactorModel subclass (FF3, FF5, Carhart4); a model that fits with fewer than 30 valid estimation observations (the same recommended minimum as validate_task()'s default) now emits one advisory warning in both modes. PatellZTest's k is now read explicitly from each model's statistics$n_params (MarketModel 2, FF3 4, Carhart4 5, FF5 6, CPMA 1, MarketAdjusted 0) instead of being derived as length(resid) - df (which was silently wrong whenever df reflected an unrelated correction); m now counts finite estimation-window abnormal returns instead of the raw row count. MarketModel's forecast-error correction now uses complete pairs only for mean(Rm_est)/SS_market, matching exactly the rows lm() used.
• **A7 -- CalendarTimePortfolioTest denominator redefined to the Brown-Warner (1980, 1985) estimation-window AAR standard deviation.** Previously ts_sd was computed from the event-window portfolio series itself (self-referential with the numerator, so a larger event-day shock inflated both). caltime_t/ccaltime_t now use degrees of freedom n_estimation_days - 1, exposed as attr(result, "caltime_df") and read by both adjust_p_values() and tidy(). **This is a valid-input redefinition:** caltime_t/ccaltime_t values differ from the initial 0.66.0 submission; golden values are re-pinned.
• **A8 -- MarketAdjustedModel's forecast-error correction is now forecast_error_corrected_sigma == sigma exactly** (correction factor 1), because the model estimates nothing from the estimation window. Previously it wrongly reused the constant-MEAN correction formula (sigma * sqrt(1 + 1/m)), which is only valid for a model that DOES estimate one parameter (a mean), like ComparisonPeriodMeanAdjustedModel (unchanged). **This is a valid-input redefinition;** golden values are re-pinned.
• **A9 -- Sign convention unified to strict n_pos = sum(AR > 0) / n_neg = sum(AR <= 0)** in CSectTTest, PatellZTest, and CalendarTimePortfolioTest (previously >= 0/< 0), matching the pre-existing SignTest convention. An abnormal return of exactly 0 now counts as non-positive everywhere.
• **A10 -- TestStatisticBase$confidence_type is now validated** with match.arg(c("two-sided", "less", "greater")) (an invalid value errors) and emits one warning at construction when a non-default value is supplied, stating that every p-value in EventStudy is currently two-sided and the value has no effect. No p-value formula changed; one-sided p-values are not implemented.
• **A11 -- BMPTest roxygen documentation corrected (docs-only, no formula change).** The docstring incorrectly claimed standardization by the forecast-error-corrected sigma; both BMPTest and KolariPynnonenTest standardize by the MODEL sigma (model$statistics$sigma), which is what the code always computed.
• **A12 -- bootstrap_test() observed/draw construction aligned; NA draws excluded from the p-value denominator.** observed_caar now uses the SAME per-event coalesce-to-0 CAR construction as the bootstrap draws (matches cumsum(observed_aar) exactly on NA-free input, but differs from it under a partial-window gap, where the per-event construction is correct). A bootstrap draw whose statistic is NA (e.g. a sign-flip combination that zeroes the cross-sectional SD) is now excluded from BOTH the exceedance count and the denominator, instead of being counted as "did not exceed" while still inflating n_boot + 1. The bootstrap weight clustering unit (firm_symbol) is confirmed correct and unchanged.

API and documentation consistency (2026-09-24 re-evaluation)

• **B1 -- ModelBase, TestStatisticBase, and ReturnCalculation are now exported** with roxygen documenting the subclass contract expected by run_event_study() (fit()/abnormal_returns(), compute(), calculate_return(), and the statistics fields consumed downstream, including the optional n_params field added by A6). Previously these base classes existed but were unexported, so vignettes and skills advertising "subclass ModelBase" referenced a symbol users could not actually reach with EventStudy::ModelBase.
• **B5 -- generics::tidy(task) now dispatches to tidy.EventStudyTask().** generics added to Suggests; tidy.EventStudyTask() remains directly callable and exported as before.
• **B2 -- Vignette code examples fixed to the real function signatures.** modern-did-estimators.Rmd and automated-reports.Rmd previously called PanelEventStudyTask$new() with non-existent arguments (data/unit_col/time_col/treatment_col/outcome_col); fixed to the real (panel_data, unit_id, time_id, outcome, treatment, treatment_time). cross_sectional_regression(characteristics = ...) fixed to data = .... automated-reports.Rmd's "Available sections" table and every sections = c(...) example previously listed section keys (summary, data, single_event, multi_event, cross_sectional, panel) that do not exist in the report template; corrected to the real keys (exec_summary, data_methods, results, diagnostics, robustness, references, appendix).
• **B4 -- pkgdown reference reorganized.** statistical-conventions added as an article; dieselgate/earnings_surprises now listed explicitly in "Data & Datasets"; degenerate-input-contract, eventstudy-shape-contracts, and eventstudy-deprecation grouped under a new "Contracts & Lifecycle" reference section; report_table added to "Export & Reporting" and its \keyword{internal} tag removed (it is exported and advertised).
• **B6 -- Unused DT and patchwork removed from Suggests.** download_stock_data()'s quantmod fallback branch now guards zoo::index() with its own requireNamespace("zoo") check before any download.
• **B7 -- .claude/skills/es-capabilities/SKILL.md signatures corrected** for run_event_study() and validate_task() to match formals(); a scripted scan of every vignette/README/skill code chunk confirms zero remaining argument-name drift against the installed package.
• **B3 -- .claude/skills/es-advisor/reference/interpreting-diagnostics.md rewritten to the real es_diagnostics() structure** (meta, estimation_window, event_window, cross_sectional, contract_state, aggregate_summary), verified field-by-field against a live run, with the 8 offline knowledge-base rule thresholds restated in terms of the real field paths they key off. The previous version documented a fabricated structure (n_events, per_event, mean_r_squared, etc.) that did not exist on the returned object.

Testing (2026-09-24 re-evaluation)

Test-suite quality hardening so vacuous or always-skip tests no longer mask

regressions, and so the full NOT_CRAN=true suite runs with WARN 0

(every warning a test triggers is now explicitly expected by class/regexp,

or muffled at its source when the fixture is intentionally short).

• **C1 -- adjust_p_values()** gains explicit-formula tests for its KolariPynnonenTest, GeneralizedSignTest, RankTest and CalendarTimePortfolioTest branches, comparing against 2*pt(-abs(t), df)/2*pnorm(-abs(z)) directly.
• **C2 -- Vacuous regression tests made real:** the bootstrap firm-clustering test now hand-replicates the wild-bootstrap algorithm (one weight per unique firm_symbol) and shows it differs from an event-level clustering alternative on the same seed; the two Patell Q_i tests now assert the exact aar_z from an independent hand computation (k=2 and k=4); the LinearFactorModel FEC test now asserts the exact hat-matrix value sigma*sqrt(1+h_t); the HAC-SE test now asserts equality with sandwich::NeweyWest() on the same lm() fit.
• **C3 -- Panel TWFE tests tightened to golden checks** against a direct lm() two-way-fixed-effects fit on the same deterministic seeded fixture (static_twfe estimate + cluster-robust SE; dynamic_twfe every non-base event-time coefficient), replacing the previous loose numeric bounds.
• **C4 -- .rank_events_for_cap() real test:** an event genuinely unfitted via a degenerate estimation window (with its one contract warning asserted explicitly) is shown to always rank first (anomaly score Inf) and always survive a max_events cap, replacing the previous unconditional skip().
• **C5 -- DCC-GARCH / MarketModel FEC tests de-guarded:** the DCC-GARCH test no longer swallows errors in a tryCatch()-to-TRUE handler; it now asserts is_fitted unconditionally and skips ONLY on a narrowly-matched non-convergence warning. The MarketModel FEC "effective obs count" test no longer hides its assertions behind if (is_fitted).
• **C6 -- .try_download() narrowed** to convert only network/HTTP-style failures into skip() (by condition class when available, otherwise a narrow message pattern); any other error (a parse/logic bug) now fails the test. Covered by two new direct tests of the helper itself.
• **C7 -- Every test_that() block that draws random numbers without its own seed now has one**, across test_edge_cases.R, test_models.R, test_multi_event_statistics.R, test_cross_sectional.R, test_synthetic_control.R and test_intraday.R; test_intraday.R's Sys.time()-based fixtures were replaced with fixed UTC POSIXct literals.
• **C8 -- High-value numeric assertions added** to test_execute.R (each exercised model's AR/alpha/beta checked against a direct lm() or arithmetic computation) and test_export.R (exported CSV AR/CAR/AAR values checked to equal the task's own values, round-tripped through the file).
• **C9 -- Test-file organization:** the full-pipeline CalendarTimePortfolioTest case moved from test_bhar_test_statistics.R to test_multi_event_statistics.R (it is not a BHAR test); the browser()-source-grep check in test_aar_test_statistics.R replaced with a behavioural PatellZTest$compute() test against a hand computation; the single weak test in test_caar_test_statistics.R folded into a real numeric CSectTTest check.
• **C10 -- No leaked warnings.** Every warning a test triggers is now either asserted explicitly (expect_warning(..., regexp = / nested for multiple independent warnings) or muffled by class via the new muffle_short_window() helper (tests/testthat/helper-warnings.R) for fixtures whose short estimation window is intentional (golden/invariant/ numerical-stability fixtures, never a blanket suppressWarnings()). A new test_execute.R test locks that fit_model() collapses N short-window events into exactly ONE eventstudy_short_estimation_window warning listing the event ids.

API Stabilization & Deprecation Lifecycle (Phase 28)

This release completes a signature-consistency audit of the full public API and

wires a formal deprecation lifecycle (base .Deprecated() + optional

lifecycle shim). All deprecated argument names continue to work and emit

exactly one deprecation warning pointing to the replacement.

Renamed Arguments (deprecated old names still work)

• plot_stocks(): do_sample is deprecated in favour of sample_symbols (#APIS-01). The new name is noun-first, consistent with the sibling parameter max_symbols. Pass the old name and you receive one deprecation warning; the result is identical. (#APIS-04)

Deprecation Infrastructure

• New internal helper .deprecate_arg() in R/deprecation.R. Always calls base .Deprecated() unconditionally; additionally calls lifecycle::deprecate_warn() when lifecycle is installed (Suggests-only, never a hard dependency). (#APIS-04)

Return-Shape Contracts (opt-in, default-off)

• New R/shape_contracts.R provides an opt-in return-shape contract for the pipeline's result tibbles. Enable with options(EventStudy.shape_contracts = TRUE). When enabled, the pipeline checks that the column names and types of the single-event statistics tibbles (ART, CART) and the multi-event AAR/CAAR tibble (CSectT) match the canonical expected shapes. On any mismatch exactly one warning() is emitted naming the context and the specific drift; the contract never calls stop(). Correctly-shaped is_fitted = FALSE degenerate outputs (same column names, NA-propagated values) are treated as valid shapes and produce no warning. The option defaults to FALSE so valid-input behaviour and the existing test suite are completely unaffected. (#APIS-02)

Install-Tested Multi-OS CI (Phase 29)

• The GitHub Actions workflow now runs rcmdcheck against the *installed* package (not load_all) across multiple operating systems, catching install-vs-load_all divergence in NAMESPACE/imports before it reaches CRAN.
• A dedicated CI leg runs with _R_CHECK_FORCE_SUGGESTS_ forced on, exercising every optional-Suggests code path so the requireNamespace() guards are verified end-to-end.
• report_table() is now an exported function; the public API snaps