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Hello everybody, in one of the clinical projects we consult on data analysis, I am facing a problem I have not yet come across and that leaves me with no idea on how to proceed. The problem pertains to the dimension of the outcome data set. In a repeated measures design, let N be the number of people treated and T be the number of measurement occassions. I understand that N=1 (or _some_) more and T=120 would make up a time series, and that I am supposed to fit ARIMA-MOdels or Transfer functions. I could detect effects by structural breaks around the point of time of intervention, that is: performing intervention analyses as proposed in McDowell, McCleary, Meidinger and Hay, 1980, Interrupted time series analysis, or other books on how to analyse data from single subject designs. Allright. I understand that N=120 (or any number more) and repeated measures like 2<=T<="the-smaller-the-better" would make up a dataset suitable for an ANOVA approach or mixed models using special covariance structures like SAS's proc mixed. I know how to do that. Allright. I understand that for each of this variants there are some alternatives in statistical modeling (like non-parametric analyses etc.). Now, what am I supposed to do with data from a design giving a T=120 time series for _each_ of 120 subjects ? There has been a controlled study where patients in three independent groups were asked to keep a diary on some outcome variables for ca. 4 months. There are some design variables like treat/control or sex and age that are expected to contribute systematically to variation between outcome measures. But this outcome measure apparently is a time series. I don't think I should perform an ANOVA-style analysis with a 120-level time factor. Pooling data and performing ARIMA/transfer-functions on a single time series of subjects' means for each point in time doesn't make sense either, assuming that subjects differ in both measurement level and covariance structure of their individual time series. I admit that I have no idea how to evaluate, say, an effect of treatment on this kind of outcome measure. Does anybody else have an idea ? I promise to post a summary of res- ponses to the list. Thanks in advance Hans-Christian Waldmann --------------------------------------------------------------------- Dr. Hans C Waldmann Methodology & Applied Statistics in Psychology & the Health Sciences ZFRF / University of Bremen / Grazer Str 6 / 28359 Bremen / Germany [log in to unmask] / http://samson.fire.uni-bremen.de friend of: AIX PERL ADABAS SAS TEX --------------------------------------------------------------------- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%