zhongmiao wang <zhongmiao <at> gmail.com> writes: > I am studying the effect of schools on student achievement growth over > time. School effect is random. The effects of schools in prior years > are assumed to be persistent till the current year. Thus, the total > school effect in the second year is like J=J2+J1. Does anyone know how > to model this kind of cumulating random effects in lmer? Thanks in > advance!
Compute new variables with the cumulative effect of the previous years and use these instead of J2, J1. If there are not too many years, using "reshape" to make a "wide" version of the data frame, and then adding up within a row is probably the most transparent way to do this. Dieter ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
