# REndo 2.5.0

### NEW FEATURES
* We add the `copulaIMA` method which implements the copula-based Instrumental Variable Model (IMA) proposed by Haschka (2025)

### MAINTENANCE
* Fix CRAN notes regarding tests for `multilevelIV` and HTML issues in the documentation



# REndo 2.4.11

### MAINTENANCE
* Fix CRAN notes regarding tests for `multilevelIV`



# REndo 2.4.10

### NEW FEATURES
* The Pstar data generated in `copulaCorrection` is improved with the corrections proposed by Qian, Koschmann, and Xie (2024)

### MAINTENANCE
* Fix CRAN notes regarding documentation



# REndo 2.4.9

### MAINTENANCE
* Add CITATION file and references to forthcoming JSS publication
* Fix missing package alias



# REndo 2.4.8

### MAINTENANCE
* Replace data set `dataCopDisCont` with a new one



# REndo 2.4.7

### MAINTENANCE
* Fix tests due to changes in package dependencies



# REndo 2.4.6

### MAINTENANCE
* Replace data sets with new ones
* Fix tidy HTML warnings in documentation and parsing of news.md reported in daily CRAN checks



# REndo 2.4.5

### BUG FIXES
* Fix broken correctness tests for `latentIV` on M1mac.

### MAINTENANCE
* Update maintainer email.



# REndo 2.4.4

### BUG FIXES
* Fix documentation to conform to HTML5.



# REndo 2.4.3

### BUG FIXES
* In method `multilevelIV` matrices could not be constructed if all groups were of the same size. Thanks to pinson06 for reporting.



# REndo 2.4.2

### BUG FIXES
* In the `copulaCorrection` method with a single endogenous regressor the correlation coefficient rho was wrongly constraint to [0, 1] instead of to [-1, 1]. Further, rho was not included in parts of the calculations. Special thanks to Fredrik Falkenström for reporting this observation!



# REndo 2.4.1

## SIGNIFICANT USER-VISIBLE CHANGES
* Allow using the method `copulaCorrection` with a single endogenous regressor



# REndo 2.4.0

## SIGNIFICANT USER-VISIBLE CHANGES
* Add a formal assumption test for method `hetErrorsIV` to detect weak instruments

## NEW FEATURES
* The log-likelihood function underlying `copulaCorrection` case 1 is refactored and implemented using Rcpp and RcppEigen what makes it considerably faster
* Improved checks of user input that disallow any non-finite values in the data
* New data was generated for `dataHetIV`



# REndo 2.3.1
* None. Version bump in order to resubmit to CRAN after package was archived.



# REndo 2.3.0

### SIGNIFICANT USER-VISIBLE CHANGES
* Add support for predictions through method `predict` for every model

### BUG FIXES
* Fix wrong calculations for the fitted values and residuals in the enhanced OLS cases of `copulaCorrection`
* Improved documentation



# REndo 2.2.1

### SIGNIFICANT USER-VISIBLE CHANGES
* To tweak the lmer model fit in `multilevelIV` to their linking, users can supply a parameter `lmer.control`

### NEW FEATURES
* Warning in `confint` if there are NAs in the bootstrapped estimates for `copulaCorrection`
* Updated vignette

### BUG FIXES
* The coefficient estimates for `multilevelIV` are more consistent and independent of data sorting due to different standard settings for fitting `lmer`
* Bootstrapped parameter estimates for `copualCorrection` result in fewer NAs when using L-BFGS-B as optimization method



# REndo 2.2.0

### SIGNIFICANT USER-VISIBLE CHANGES
* The augmented OLS method in `copulaCorrection` also bootstraps parameter estimates
* The summary output for results from `copulaCorrection` was adapted to reflect that standard errors are bootstrapped
* Removed support for the S3 method `labels` because of inconsistent behavior across methods

### NEW FEATURES
* Bootstrapping for `copulaCorrection` case 1 is now considerably faster
* New data was generated for `dataMultilevelIV`

### BUG FIXES
* The sigma matrix in `latentIV` is constructed as in the paper by Ebbes et al. what improves results. Special thanks to Jordan Henderson for investigating and pointing this out!
* In `latentIV`, the parameter for group membership (`theta5`) is now transformed back and reported correctly.
* The vcov matrix for `latentIV` is corrected for the transformation in `theta5`.
* The bootstrapping in `copulaCorrection` case 1 now creates samples of the same length as the original data
* The (percentile) confidence intervals and vcov for results from `copulaCorrection` now rely on bootstraping



# REndo 2.1.0

### SIGNIFICANT USER-VISIBLE CHANGES
* The reworked method `multilevelIV` and accompanying data was added back to the package
* Vignette `REndo-introduction` was added to showcase package usage
* Users can supply a parameter `optimx.args` to tweak the LL optimization to their liking

### NEW FEATURES
* Method `confint` was added for methods `latentIV` and `copulaCorrection`
* Examples and documentation were improved for all methods
* New data was generated for `dataHetIV`
* The default number of iterations for all optimizations was increased to 100'000

### BUG FIXES
* To avoid infrequent warnings, the parameter `sigma` used in `copulaCorrection` was constrained to > 0
* Various spelling mistakes were fixed



# REndo 2.0.0

### SIGNIFICANT USER-VISIBLE CHANGES
* Remodeled all methods' user-interface
* Added detailed input checks for every provided parameter
* Adapted all visible outputs
* Parameter `verbose` allows to turn on or off printing
* Updated documentation to reflect all changes and added theoretical background

### NEW FEATURES
* Formulas support transformations
* Improve all code to be more reliable and stable
* Provide new example datasets and accompanying documentation for all methods
* Added extensive testing for all aspects of the package
* Increased numerical stability for log-likelihood optimization methods `latentIV` and `copualCorrection`

### BUG FIXES
* Many

### DEPRECATED AND DEFUNCT
* The multilevel function is temporarily removed from the package due to ongoing work on it
