# Factor Analysis or Cluster Analysis?
**URL:** https://boards.straightdope.com/t/factor-analysis-or-cluster-analysis/148510
**Category:** Factual Questions
**Created:** [January 14, 2003, 2:42pm UTC](https://boards.straightdope.com/t/factor-analysis-or-cluster-analysis/148510 "2003-01-14T14:42:17Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@jharding](https://boards.straightdope.com/u/jharding)
#### Post date: [January 14, 2003, 2:42pm UTC](https://boards.straightdope.com/t/factor-analysis-or-cluster-analysis/148510/1 "2003-01-14T14:42:17Z")
What are the rules governing the use of these two statistical procedures?
Both are data reduction techniques, but I’m unclear on when one should be used in lieu of the other. Any social scientists out there able to offer any guidelines or rules of thumb?
Thanks.
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### Author:  [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)
#### Post date: [January 14, 2003, 3:39pm UTC](https://boards.straightdope.com/t/factor-analysis-or-cluster-analysis/148510/2 "2003-01-14T15:39:50Z")
IIRC, cluster analysis is a method used to tell you what groups of objects are the most similar. If you had 56 different kinds of chocolate, and you wanted to break them into rough groups, you’d use cluster analysis.
Factor analysis is a technique to reduce the number of variables you’re dealing with. Ironically, I studied factor analysis and not cluster analysis, but I can only describe the latter.
We used [this book](http://www.amazon.com/exec/obidos/tg/detail/-/0130925535/qid=1042558738/sr=8-3/ref=sr_8_3/102-5902893-8053702?v=glance&s=books&n=507846) in my multivariate stats class, and it’s pretty good. It covers both of these topics.