NEWS

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undidR 3.0.2 (2026-03-02)

• Computation of HCCMEs is now faster by using a crossproduct approach rather than constructing a full omega matrix.
• Changed the default HCCME from HC3 to HC1 (i.e., hc = 1).
• Fixed an issue where standard errors were returning NA for certain edge cases.

undidR 3.0.1 (2026-02-16)

• Added the lwd and legend parameters to the S3 plot() method for UnDiDObj which controls line width and legend locations, respectively. Removed the default titles of plots.
• Also made other minor aesthetic changes to the default plots, such as adding horizontal bars to the ends of the event study plot confidence bands (like the letter I).
• Removed "none" as an aggregation option for staggered adoption.

undidR 3.0.0 (2026-01-26)

• Added new aggregation methods for staggered adoption: "sgt", "time", and "none".

  • "sgt" computes subaggregate ATTs for each treatment-time and post-treatment period pair, further separated by silo.
  • "time" computes subaggregate ATTs grouped by time since treatment.
  • "none" skips subaggregate ATT computation and directly computes the aggregate ATT from the underlying differences.

• undid_stage_three() now returns an object of class UnDiDObj, providing a unified S3 interface.

  • Added S3 methods: print(), summary(), coef(), and plot().

• Added support for event study plots via the plot() method for UnDiDObj objects.

• Added randomization inference p-values for subaggregate ATTs.

• Fixed a miscalculation of jackknife standard errors and p-values.

• Expanded weighting options for ATT computation: "none", "diff", "att", and "both".

  • "diff" applies weights when computing subaggregate ATTs.
  • "att" applies weights when aggregating subaggregate ATTs.
  • "both" applies weighting at both stages.
  • "none" disables weighting entirely.

undidR 2.0.0 (2025-05-31)

• start_time and end_time columns are now stored as strings in the format specified by date_format column in the empty_diff_df CSV file.
• Fixed as.Date() calls in undid_stage_two(), undid_stage_three(), and plot_parllel_trends() to ensure compatability for R versions 4.0.0 and onwards.

undidR 1.0.2 (2025-04-27)

• Made compatible for R versions 4.0.0 onwards.

undidR 1.0.1 (2025-02-24)

• Fixed the miscalculation of standard weights during stage two under common adoption scenarios.

undidR 1.0.0 (2025-01-23)

• Initial CRAN submission.
• Updated installation instructions.

undidR 0.1.0

• Initial development version (not yet submitted to CRAN).
• Provides a framework for implementing difference-in-differences with unpoolable data.