Is PSPP a replacement for SPSS?

PSPP is sometimes touted as a replacement for SPSS (including by its creators). Well, it isn’t (this is often the case with open source alternatives; the ambition and reality do not quite match). By stating plainly that PSPP is not a replacement for SPSS, I don’t mean to dismiss PSPP.

psppFirst off, PSPP is under active development, and getting hold of the latest version can be a bit difficult. For Windows, this site often has the most up-to-date version, for Linux/Debian you’ll need to be on a “unstable” release or compile your own (which I doubt many will want to do given that we’re looking at an SPSS replacement, not R or Octave).

Second, recent releases cover many basic functions needed for an introductory statistics course. The GUI frequently lags a bit the underlying capability, so some functions will only be available using SYNTAX. Oddly enough, the PSPP team copy the SPSS interface quite well, including things that could readily be improved (e.g. why do we have tabs for the “Data View” and the “Variable View”, but a separate window for the results or syntax? Why mix the two?).

So PSPP can readily do tables, ANOVA, linear and logistic regressions, and recoding variables. Unfortunately, and this is why PSPP is not even a replacement for basic SPSS users, there are bits and pieces missing even in the basic functions. On the positive side, PSPP has a cleaner interface than SPSS, on the negative side some features are just not there. Unless users follow a course designed specifically with PSPP in mind, they will frequently hit a wall. The same is the case for SYNTAX. Users will be able to run SPSS syntax with no problem, as long as PSPP has the commands implemented. Again, when using code from the many websites helping SPSS users, unfortunately PSPP users will frequently hit a wall.

What do I mean by bits and pieces missing? Let’s take a linear regression. It’s there, the familiar box with arrows to choose variables. Now I may want some multi-collinearity statistics, too. Ah, sorry, doesn’t exist yet. So I can build a model, but do not even have one of the most basic means to check whether it is any good. For this reason I am not surprised nobody has written an that there are not many introductions into statistics using PSPP… it’s just not there yet.

One thing I missed a lot is that PSPP does not remember the last input. So if I run a regression and want to add another variable, I’ll have to start from scratch in PSPP, entering each variable. Graphing is lacking or very poor.

With the advancements in Rstudio, R Commander, etc., I sometimes wonder whether PSPP is just advancing too slowly. Having said all this, I wanted to add on a positive note. PSPP has got quite stable in recent releases; it’s got a price tag hard to beat and moral superiority with being truly open source. And finally, it is fast, much faster than SPSS!

New Version of R Package agrmt

This week, a new version of the R package agrmt saw the light of day. I have been contacted because one of the functions in the package didn’t produce the right answers. I really appreciate this (the contacting), because it allowed me to fix the code. It was a matter of mixing up i and j. The first reaction in this case is always the worst: what if I got it all wrong? What if I can’t find the bug? To me, fixing code in my packages is important — not because of the undeniable satisfaction from getting it right — but because it is a small way to give back to the (virtual) community that gave us R and the many packages that come along with it.

The package, by the way, implements measures of agreement (consensus) in ordered rating scales, especially Cees van der Eijk’s (2001) measure of agreement A, but also measures of consensus (dispersion) by Leik, Tatsle and Wierman, Blair and Lacy, Kvalseth, and Berry and Mielke. Moreover, it implements Galtung’s AJUS for R.