[recardona]

I do a lot of stat. analysis and I was impressed with the clarity of the analyses. However, I ran through the Obama v. Romney tutorial and was surprised to see that the software was averaging survey items (Likert-scale data). I thought that this was not allowed since it is troublesome to interpret the output (how do you interpret 8.36 Neuroticism?)

Aside from that, I can see this filling a need for those whom are aware of the importance of statistical significance but do not have the time to look up the appropriate analysis function in R/SAS/SPSS/...

[mgurlitz]

You're right, they shouldn't be making that average. Specifically, Likert data is ordinal, meaning 14 is less than 15 and greater than 13, but the gap between 15 and 14 may be different than 14 and 13.

For example, let's say people measure neuroticism exponentially, and an increase of one point means 10x perceived neuroticism. Because mean(log(x)) != log(mean(x)), the average won't be representative.

Everything else looks OK though: count, median, percentiles, a histogram.

[glaugh]

Thanks for the comment.

Agreed, Likerts are definitely an area of controversy.

A couple references from Wikipedia about Likert-as-continuous:

Pro: http://www.ncbi.nlm.nih.gov/pubmed/20146096

Con: http://xa.yimg.com/kq/groups/18751725/128169439/name/1Likert...

Our stance is generally a pragmatic one. It's very common practice to analyze data this way, so we enable it. But if you want to analyze your Likerts as ordinal data, you can change the variable type to Ranks (ie Ordinal), where we handle the result as you'd expect (nonparametric test, no averages). Note that this feature is disabled in the demo.

Thanks!

edit: formatting