## Wednesday, July 23, 2014

### Detteman's Laws of Individual Differences: Repost of Dec 22, 2008 post

I just learned that the link to the PDF file referenced in an old post was dead.  I just fixed it an am re-posting that original post in case others have been frustrated by the broken link.

Early in my career I ran across a tremendous tongue-in-check book chapter by Doug Detterman where he articulated Detterman's Laws of Individual Differences (click here to view--you will need to rotate in your pdf reader). Many of the laws make me laugh to this day. All serious individual difference psychologists (psychometrics, intelligence researchers, developers and users of intelligence tests) should read these from time-to-time....to regain perspective on research in this area. You can read them for yourself...but below are a few of my favorites:

Laws of statistical inertia

• Law II. Anything which exists can be measured incorrectly
• Law III. Incorrect measurements require intelligent application of appropriate statistics to be interpretable
• Law IV. It can't be done.
• Law VII. Everything is correlated with everything else.
• Law VIII. Never factor analyze anything - this is one of my absolute favorites, esp. his further explation.....it is impossible to conduct a factor analysis correctly on data which are completely suitable......determining an acceptable rotation has never been accomplished by anyone in the history of Western Civilization..it is impossible to name factors and still have friends...
• Law X. The less frequently used multivariate techniques...must be left to the experts.
• Law X (corrlary 1). There are no experts in the less frequently used multivariate techniques.
• Law XIII. The potential usefulness of any statistical technique is directly proportional to the impossibility of its correct application.

Laws of research strategy.

• Law XV. My area is best
• Law XVI. Always remember you are bringing religion to the heathen.
• Law XVIII (corralary 1). Awlays use models at least ten years old.
• Law XVIII (corralary 2). Never blame the model.

Laws of creative research interpretation

• Law XXI. Lacking reliability and/or validity, theorize.
• Law XXII. Having obtained reliability and/or validiy, theorize elaborately
And many others..............a classic in the field..