What's New?

• 2.4-20 (October 24, 2011): bug fix for GAM models (thanks to Felix Thoemmes)
• 2.4-18 (April 26, 2011): JSS version, no change in code.
• 2.4-17 (April 2, 2011): a minor documentation fix.
• 2.4-16 (January 8, 2011): a bug fix for user defined distance.
• 2.4-15 (December 11, 2010): a bug fix in the mahalanobis matching.
• 2.4-14 (August 12, 2010): a bug fix in match.data() so that it can be called within a function (thanks to Ajay Shah, George Baah, and Ben Dominique); MATCHITnow does not specify digits for printing (thanks to Chris Hane); A summary table of matched data is now stored in the output (thanks to George Baah)
• 2.4-11 (June 25, 2009): More flexible inputs in plotting.
• 2.4-10 (February 2, 2009): Minor documentation fixes
• 2.4-8,2.4-9 (January 29, 2009): Minor documentation fixes
• 2.4-7 (August 4, 2008): Fixed minor bug in subclassification (thanks to Ben Domingue)
• 2.4-6 (July 21, 2008): Improved summary object for exact matching (thanks to Andrew Stokes)
• 2.4-5 (July 20, 2008): Fixed a minor bug.
• 2.4-4 (July 18, 2008): Fixed another bug with regard to the discard option (thanks to Ben Dominique).
• 2.4-3 (July 18, 2008): Fixed a bug in full matching regarding the discard option (thanks to Ben Dominique). Some updates of documentation regarding coarsened exact matching (2.4-1 and 2.4-2).
• 2.4 (June 12, 2008): Included coarsened exact matching; documentation bug fixes (thanks to Will Lowe)
• 2.3-1 (October 11, 2007): Stable release for R 2.6. Documentation improved. Some minor bug fixes and improvements.
• 2.2-14 (September 2, 2007): Stable release for R 2.5. Documentation improved for full matching. (Thanks to Langche Zeng)
• 2.2-13 (April 10, 2007): Stable release for R 2.4. Additional fix to package dependencies. Bug fix for summary().
• 2.2-12 (April 6, 2007): Stable release for R 2.4. Fix to package dependencies.
• 2.2-11 (July 13, 2006): Stable release for R 2.3. Fix to ensure summary() command works with character variables in dataframe (thanks to Daniel Gerlanc).
• 2.2-10 (May 9, 2006): Stable release for R 2.3. A bug fix in demo(analysis) (thanks to Julia Gray).
• 2.2-9 (May 3, 2006): Stable release for R 2.3. A minor change to DESCRIPTION file.
• 2.2-8 (May 1, 2006): Stable release for R 2.3. Removed dependency on Zelig (thanks to Dave Kane).
• 2.2-7 (April 11, 2006): Stable release for R 2.2. Error message for missing values in the data frame added (thanks to Olivia Lau).
• 2.2-6 (April 4, 2006): Stable release for R 2.2. Bug fixes related to reestimate in matchit() and match.data() (thanks to Ani Ruhil and Claire Aussems).
• 2.2-5 (December 7, 2005): Stable release for R 2.2. Changed URL of WhatIf to CRAN.
• 2.2-4 (December 3, 2005): Stable release for R 2.2. User's own distance measure can be used with MATCHIT (thanks to Nelson Lim).
• 2.2-3 (November 18, 2005): Stable release for R 2.2. standardize option added to full matching and subclass (thanks to Jeronimo Cortina).
• 2.2-2 (November 9, 2005): Stable release for R 2.2. optmatch package now on CRAN. Changed URL for that package.
• 2.2-1 (November 1, 2005): Stable release for R 2.2. balance measures based on empirical CDF are added as a new option standardize in summary().
• 2.1-4 (October 14, 2005): Stable release for R 2.2. strictly empirical (no interpolation) quantile-quantile functions and plots are used.
• 2.1-3 (September 27, 2005): Stable release for R 2.1. automated the installation of optional packages. fixed a coding error in summary(), the documentation edited.
• 2.1-2 (September 27, 2005): Stable release for R 2.1. minor changes to file names, the option "whichxs" added to the plot(), major editing of the documentation.
• 2.1-1 (September 16, 2005): Stable release for R 2.1. Genetic matching added.
• 2.0-1 (August 29, 2005): Stable release for R 2.1. Major revisions including some syntax changes. Statistical tests are no longer used for balance checking, which are now based on the empirical covariate distributions (e.g., quantile-quantile plot).
• 1.0-2 (August 10, 2005): Stable release for R 2.1. Minor bug fixes (Thanks to Bart Bonikowski).
• 1.0-1 (January 3, 2005): Stable release for R 2.0. The first official version of MATCHIT