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Showing posts from December, 2011

Fractional Factorial Experiments and Surveys

I'm reading and greatly enjoyed Statistics for Experimenters. The book emphasizes careful thinking about experimentation in addition to careful explanation of statistical methods.

One of the main topics is the use of fractional factorial designs. In these designs, some of the experimental conditions are confounded with higher order interactions (the latter are assumed to be negligible). These designs can be more efficient when the assumptions are correct. And fitting these designs into a sequence of experiments can make them very powerful.

This has me thinking about how we often conduct experiments on surveys. We often vary a single factor and then report the results with a slim description of the other "essential survey conditions" -- i.e. other factors which are not explored. These other conditions are potential confounders in these experimental designs.

If more of these essential conditions were reported, it might help make sense of experimental results that are somet…