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RLH in MaxDiff

I found the following table in the MaxDiff manual:

Items per Set    Suggested Minimum Fit.   
2    .574   
3    .371   
4    .282   
5    .227   
6    .191

This is for a case of 20 items where each item shown four times to each respondent.  Can somebody show me how the null RLH is developed here?   Thanks!
related to an answer for: RLH benchmark
asked Jun 23, 2014 by HongHu Bronze (835 points)

1 Answer

0 votes
Directly below that table, the documentation explain how those values were developed:

"Technical Notes:  We simulated 1000 respondents answering randomly to each questionnaire, then estimated the scores using HB: prior variance=2, d.f.=5.  Both "best" and "worst" answers were simulated for each respondent (with the exception of the 2 items case).  For each simulated data set, we sorted the respondents' fit statistics from highest to lowest and recorded the 95% percentile fit.  If asking only "bests," because the amount of information for each respondent is reduced, the Suggested Minimum Fit would be higher."
answered Jun 23, 2014 by Bryan Orme Platinum Sawtooth Software, Inc. (180,515 points)