Monday, December 5, 2011

Considering a Switch to SPSS: What are Pitfalls and Benefits?

My well worn 4 year old Compaq desktop, from which I do most of my statistical analysis, is finally getting slow enough that I need to get a new computer.  The rest of the computers, phones, and tablets in my house are Apple product, so I am looking at getting a Mac Mini.  I'll be reusing all the rest of the peripherals from the Compaq for now as they work fine and I am not hung up on getting their Mac equivalents.  However, this switch in computer hardware and thus OS is presenting an interesting opportunity for me.

I have an older version of Minitab that I run for most back end analysis for this blog.  I then export Minitab's results to Excel 2010 to make the graphical presentation of the data look a whole lot better.  I've learned to use Minitab via my Six Sigma training, and it's very useful for what I do.  The trouble is, I only have a Windows version of it and would really prefer to not have to constantly switch over to the Windows OS via Boot Camp on the Mini whenever I want to do analysis and/or blog.  It kind of defeats the purpose of getting the Mini.  I'd like to do the analysis and blogging while running Mac OS.  Here's the trouble - a Minitab license for a Mac does not exists, so purchasing an update for my Mac is not possible.

Luckily, I can get a steeply discounted (and legal!) copy of SPSS for Mac OS or Windows.  We're talking less than $100 for a package that retails for $2700!  The package available to me comes with the following SPSS modules:

  • SPSS Statistics Base
  • Advanced Statistics
  • Custom Tables
  • Forecasting
  • Regression
  • Tables Original
  • Trends Original
A basic description of each module can be found here.

My concern is at a minimum maintaining the availability of analysis in Minitab.  Losing functionality I use routinely today is not an attractive thought to have  My most frequently used functions in Minitab are:
  1. Descriptive statistics: normality plot and check, mean, median, standard deviation, quartiles, etc.
  2. Normal Sample comparisons: two and one sample t and p
  3. Correlation tests
  4. Box-Cox Transforms
  5. Non-parametric tests such as Mann-Whitney
  6. Linear and Non-Linear Regression with ability to generate prediction (PI) and confidence interval (CI) data off of "new observations"
  7. Binary Logistic Regression (with PI and CI data generation capabilities)
  8. Ordinal Logistic Regression (with PI and CI data generation capabilities)
My read through of the module descriptions indicates that I'd have much, if not all of Minitab's functionality.  Items (6) through (8) seem to be pretty clearly called out in the Regression module.  What I can't seem to find much on is (4) and (5), which are critical given the non-normal nature of many data sets with which I work.  Does anyone know if the SPSS modules I listed contain features (4) and (5)?

Finally, beyond the actually calculations available, I am interested in understanding the user interface for SPSS.  My father used SPSS 30 years ago when completing his operations research masters.  It has a good bit of legacy code associated with it, much like Minitab.  That can sometimes limit the GUI overlay capabilities - Minitab can have some frustrating limitations due the legacy code.  Having no experience with SPSS, I am concerned I might run in to different limitations.  Does anyone know if SPSS's UI is as good as Minitab's or better?

Thank you to anyone who does provide feedback, and let me know of any other pitfalls or benefits I may have missed.

4 comments:

  1. Stata would be a better option than SPSS, although it might take some time to get to know how to use it.

    If you prefer GUI based packages, you should definitely take a look at GRETL. http://gretl.sourceforge.net/

    There is a native package for MacOSX, it is free, very intuitive and it seems to fit excellently your needs.

    If you are ready for a greater change, then I'd recommend GNU R, which is a powerful and free language for statistical computations, with practically endless features and beautiful graphs. However, the learning curve is quite steep.

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  2. th.alys -

    Thanks for the feedback. I downloaded GRETL tonight, and it did seem very straightforward. The only challenge I had was in attempting to plot prediction intervals. It never seemed to be able to do it, even though it appeared I was requesting it (Analysis -> Forcasts from a Binary Logit model). Any insights as to how I might be able to generate such graphs/data as it is key to my blog. Thanks again for all of your help so far!

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  3. I'm not sure what's going wrong. Take a look here http://www.learneconometrics.com/gretl/using_gretl_for_POE4.pdf

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  4. Why not use R instead of SPSS? Does everything you want and more, has very good graphics output (with some work required),is free, and is growing fast. Vast amounts of help, too

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