The Statistical Software Components (SSC) archive

The tidbit from last week described how you can view help files from the Statistical Software Components (SSC) archive over the internet. This tidbit gives a little more information about the SSC archive.

While many people and organizations host their user written Stata programs on their own web sites, the SSC archive (which is often called the Boston College Archive) is one of the largest (if not in fact the largest) repository of Stata programs contributed by Stata enthusiasts from all over the world. The ssc command, which is built into Stata, is a convenience command that easily connects you to this repository.

For example, if you type the ssc hot command, shown below, you will see the top 10 packages that have been recently downloaded. The output below shows the output that I saw executing the command today (your results will vary as the downloads for packages change over time).

. ssc hot
Top 10 packages at SSC

        Feb2011    
  Rank   # hits    Package       Author(s)
  ----------------------------------------------------------------------
     1   4404.1    outreg2       Roy Wada                                
     2   3098.8    estout        Ben Jann                                
     3   1652.5    ivreg2        Christopher F Baum, Mark E Schaffer,    
                                   Steven Stillman                         
     4   1470.2    psmatch2      Barbara Sianesi, Edwin Leuven           
     5   1034.5    gllamm        Sophia Rabe-Hesketh                     
     6   1025.3    ranktest      Mark E Schaffer, Frank Kleibergen       
     7    910.8    xtabond2      David Roodman                           
     8    749.8    tabout        Ian Watson                              
     9    706.8    xtivreg2      Mark E Schaffer                         
    10    630.0    tabstatmat    Austin Nichols                          
  ----------------------------------------------------------------------
  (Click on package name for description)

You can click on the names of the packages to view its associated help file. Viewing these different help files gives you a quick sense of the range, scope, and utility of the programs located at SSC. (Note the names of the packages in the output above are hot-linked to their online help files using the technique illustrated in the tidbit from last week).

You are not limited to just viewing the top 10 packages. For example, you can use the n() option, as illustrated below, to control how many packages you see. The example below shows the top 100 packages recently downloaded (the output is omitted).

. ssc hot, n(100)

You can see the packages that have been created or revised in the last month with the ssc new command.

. ssc new

When I executed this command, approximately 50 commands were listed that have been created or updated in the last month. This illustrates how lively the activity is with respect to updates and new contributions to the ssc archive.

Suppose that, after perusing the output of ssc new or ssc hot that you find decide that you want to install a package, for example the package called outreg2. You can then simply type

. ssc install outreg2

and that package is downloaded and installed. You can then begin using the programs described in the program. You can view the help file by typing

. help outreg2

You can learn more about the SSC archive with the help ssc command.

You can download the example data files from this tidbit (as well as all of the other tidbits) as shown below. These will download all of the example data files into the current folder on your computer. (If you have done this before, then you may need to specify net get stowdata, replace to overwrite the existing files.

net from http://www.MichaelNormanMitchell.com/storage/stowdata
net get stowdata

If you have thoughts on this Stata Tidbit of the Week, you can post a comment. You can also send me an email at MichaelNormanMitchell and then the at sign and gmail dot com. If you are receiving this tidbit via email, you can find the web version at http://www.michaelnormanmitchell.com/ .