|Subject:||Re: oblimin rotation?|
|Date:||Fri, 24 Oct 2014 07:46:40 -0500|
|User-agent:||Mozilla/5.0 (Windows NT 6.1; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0|
On 10/24/2014 7:01 AM, F. Thomas wrote:
You're not addressing John's point, which is philosophical. He says that IF there were an error in SPSS, you would never be able to tell from an audit of their code.
Furthermore, I question your faith. How would NDA (whatever that is) or any of the other organizations or individuals know that there was an error?
But, what the hack, let's answer YOUR question: I HAVE FOUND ERRORS IN BOTH SPSS and SAS on a few occasions. Just recently I used SPSS 21 to calculate means and SD's (yes, means and SD's!). First I used the descriptives subcommand of CORR (or RELIABILITIES, I cannot recall) and then later I re-calculated them using descriptives and they differed in the second or third decimal. This happens all the time when there is missing data because the samples differ and some routines (RELIABILITY, for example) force listwise deletion, but THERE WAS NO MISSING DATA in this dataset. So, that's one, and I was in EXACTLY the situation that John described because I was doing this work for hire. Luckily the client did not care about small differences.
Recently I was in a research meeting teaching some colleagues how to run a complex bit of SPSS syntax. We had three different versions of SPSS running on the same syntax using the same data on four workstations. Three of us were able to reach agreement. The fourth colleague (whose results could not be made to reconcile) was running SPSS on her Windows 8 laptop and she's now in a multivariate class and her version of SPSS doesn't reproduce the instructor's logistic regression output. Looks to me like her version of SPSS has bugs...
Back around 1990 when PROC CALIS was new and I was taking an SEM class, I found a bug in Hartmann's work. I cannot recall now what it was but it must have been glaring because I wasn't comparing software, I was just reading the output and it popped out.
There was a fairly recent version of SPSS that had a bug that prevented output from appearing. I think it was only on Windows 7 but how the hell does a version of the software slip out the door with THAT bug? That's like shipping a car from an auto factory without an engine. In fact, as far as I know, SPSS, Inc. has had to release patches for every version of SPSS to fix bugs in their software -- sometimes more than one patch. So, those patches are absolute proof that their software has bugs of some kind.
So, let's review: John's point is PHILOSOPHICAL, and he's right. Your faith is, frankly, quite childish. I have personally found bugs and furthermore it's also silly to argue that any large software package does not have bugs. If YOU haven't found errors, it's because you haven't looked hard enough.
So, to use your own words: don't exaggerate the safety of closed software.
-- Alan D. Mead, Ph.D. President, Talent Algorithms Inc. science + technology = better workers +815.588.3846 (Office) +267.334.4143 (Mobile) http://www.alanmead.org Announcing the Journal of Computerized Adaptive Testing (JCAT), a peer-reviewed electronic journal designed to advance the science and practice of computerized adaptive testing: http://www.iacat.org/jcat
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