News from SPSS Developer Central

[Peck, Jon]

The blog that Graham Wills and I are writing is moving soon to a new url as we complete the integration with the SPSS site.  The new url will be insideout.spss.com.  The old address will be redirected to the new one once it is set up.

 

There are now 8 posts on the site.  We encourage you to add your comments and propose new topics.

 

There are new items and updates on Developer Central.

 

The beta FUZZY version of the case-control matching module has been updated with a few bug fixes.  It seems pretty solid now, so I expect to remove the beta designation soon.  If anyone finds a problem with the newest version, please let me know.  It was recently tested with a control dataset of over 11,000 cases and four matching variables – two exact and two fuzzy, with good results.

 

There is a new extension command for TURF analysis.  TURF stands for Total Unduplicated Reach and Frequency.  The method is used to find frequency counts for groups of response variables accounting for duplication.  For example, you have responses to a survey listing ten flavors of ice cream.  You want to produce the three that together will reach the largest percentage of respondents.  Simple frequency counts, of course, don't tell you the best combinations because of overlap.  TURF calculates the percentages for combinations and lists those with the highest coverage.  This new download includes the SPSS syntax definition, a dialog box interface, and the implementation module.  It requires SPSS Statistics Version 17, but with two minor naming changes (spelled out in the installation instructions), it should work with Version 16, and the core Python implementation function should be usable in a program with Version 15.  It has only been tested with Version 17, however.

 

The TEXT extension command, which creates a text block in the Viewer window, has some new features.  The older version would create a block of plain text (separate from the log).  The new version can also accept html or rtf text and create a formatted block of text.  It also has the ability to insert a page break just before the text block.  These changes continue our efforts to make it easy to produce better-formatted output.  It goes along with the SPSSINC MODIFY TABLES and SPSSINC MODIFY OUTPUT extension commands.  The new features of TEXT require Version 17, but this version continues to work with Version 16 for plain text.

 

I wrote a post on the blog recently about the TEXT command.

 

There is a new extension command, SPSSINC QQPLOT2 for two-variable or two-group Q-Q plots.  While SPSS already has a facility for Q-Q plots, these compare the distribution of one variable with a theoretical distribution.  The new command compares the empirical distributions of two variables, or it compares the distributions of one variable for two subgroups of cases.  It is thus helpful in determining whether the two sets of values come from the same distribution or how their distributions differ.  The command uses an R function, so it requires the Python and R plug-ins and SPSS Version 17.  The package includes the syntax definition, a dialog box interface, and the implementation code.

 

As always, these items can be downloaded from SPSS Developer Central, www.spss.com/devcentral in the Downloads section.  It is helpful to click the single-page-view link.  The Filter list allows you to view just extension commands.  The Python and R plug-ins can be downloaded from the Plugins Download Page link on the site.

 

There are now approximately 28 extension commands available on Developer Central.  All extension commands require at least Version 16 of SPSS.  The majority require Version 17.  The dialog box interfaces provided with many of them require Version 17.  There are also many programmability modules not packaged as extension commands available.

 

We hope you find these facilities useful.

 

Jon K. Peck

SPSS Inc.

[hidden email]

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now blogging at www.spss.com/insideout