Code is substantially faster/more memory efficient

Support for

*universal*base periodMajor improvements to unit testing

Completely removed

`mp.spatt`

and`mp.spatt.test`

functions (which were the original names for`att_gt`

)Simulation/testing code now exported

Removed some slow running checks

Multiplier bootstrap code is now written in C++

Improvements to error handling, added some additional warning messages, removed some unnecessary warning messages

Bug fixes for NA standard errors that occur with very small groups

Improved plots

Maximum event time for event studies

Compute critical value for simultaneous confidence bands even when some standard error is zero (set these to NA)

Improved codes for unbalanced panel data: faster and more memory efficient

Correct estimates of P(G=g|Eventually treated) with unbalanced panel data. This affects

**aggte**objects with unbalanced panel dataBug fixes for summary

**aggte**objectsAllow clustering for unbalanced panel data

Fixed error in calendar-type aggregation within

**aggte**function (point estimates were not being weighted by group-size; now they are).Additional error handling

Big improvement on code base / functionality / testing

Deprecated

**mp.spatt**function and replaced it with**att_gt**functionCalling

**att_gt**is similar to calling**mp.spatt**; instead of formula for outcome of the form`y~treat`

, now just pass the name of the outcome variableDeprecated

**mp.spatt**function and replaced it with**conditional_did_pretest**functionNew

**est_method**parameter. Can call any function for 2x2 DID in the**DRDID**package (default is now doubly robust estimation, but inverse probability weights and regression estimators are also supported) as well as provide custom 2x2 DID estimatorsBug fixes for including groups that are

*already treated*in the first periodAllow for user to select control group – either

*never treated*or*not yet treated*Add functionality for uniform confidence bands for all aggregated treatment effect parameters

Introduced dynamic effects in pre-treatment periods. These allow for users to report event study plots that are common that include pre-treatment periods and are common in applied work. The event study plots in the

**did**package are robust to selective treatment timing (unlike standard regression event study plots)Support for using repeated cross sections data instead of panel data is much improved

Support for using sampling weights is much improved

Big improvement to website, vignettes, and code documentation

Code for dealing with unbalanced panels

Allow for event studies to be computed over subsets of event times

Allow for treatment anticipation via

*anticipation*argument

- Corrected check problems

Improved ways to summarize aggregated treatment effect parameters

Fixed bug related to needing new version of BMisc

Fixed bug related to plotting with no pre-treatment periods

Improved ways to easily plot aggregated treatment effect parameters

Added some error handling for some cases with small group sizes, and fixed some cryptic error messages

Fixes handling for data being in format besides

*data.frame*(e.g.*tibble*)Add warnings about small group sizes which are a very common source of trouble

- Updates for handling repeated cross sections data, both estimation and inference

- bug fixes for testing without covariates, allowed to pass NULL in addition to ~1

fixed issues between BMisc and formula.tools

added point estimates for repeated cross sections data

- bug fixes for the case without any covariates

- first version of package, functions for computing group-time average treatment effects, combining them into a smaller number of parameters, and pre-testing the common trends assumption