st: Non-parametric tests for survey data? (e.g., Kruskal-Wallace)

["Michael I. Lichter" <mlichter@buffalo.edu>]

I don't see any procedures for doing non-parametric tests (aside from 
chi-square in svy: tab) with complex survey data (stratified, unequal 
probabilities of selection). I am particularly looking for tests of 
difference in ordinal dependent variables across k groups (k > 2). 
Kruskall-Wallace is the most obvious test, but only available for 
non-survey data. 

I assume that these procedures are not available because (a) it's not 
clear what to do with weights in nonparametric analyses anyway (which I 
infer partly from the fact that none of Stata's nonparametric procedures 
take weights), (b) because there's no theory about whether/how they 
should work, and/or (c) because nobody has gotten around to it yet.

I'm looking for suggestions.

One possibility that comes to mind is to generate ranks using -egen- and 
analyze using -svy: mean- or -svy: reg- (I'd use one-way ANOVA if 
somebody could explain how to do it with -svy- commands). I could also 
do -svy: intreg- for the variables that represent ranges underlying 
continuous variables (since most of my ordinal variables do represent 
well-defined but unequal-sized ranges of underlying continuous 
variables, e.g., 1 = "> 1", 2 = "2-4" 3 = "5 or more"), but that would 
require -intreg- to be robust to floor effects, and I doubt that it is 
(since the method assumes an underlying Normal distribution). (I guess 
-mlogit-, -ologit- and -gologit2- are also possibilities.)

Thanks.

--
Michael I. Lichter, Ph.D.
Research Assistant Professor & NRSA Fellow
UB Department of Family Medicine / Primary Care Research Institute
UB Clinical Center, 462 Grider Street, Buffalo, NY 14215
Office: CC 125 / Phone: 716-898-4751 / E-Mail: mlichter@buffalo.edu

*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/