AR(1) growth curve model - error message

[econsic]

I am trying to estimate a growth curve model for a dataset of 9824 units clustered in 102 groups for 7 time points. I am able to estimate a model with the three levels (in order: time, units and groups) of my response variable with respect to a linear trend, Y=f(time). No other covariates are included in the model. When I try to model a first-order autoregressive covariance structure between level 1 errors (i.e. between time within unit), I meet the problem described below. Following the procedure in the MlWiN Supplement Manual (pag. 74-79 “A new method for estimating autocorrelated errors in continuous time”), when I type the command “star” the MlWiN returns the following error message: “”Design vector at level 2 is the wrong length (offs)”. I tried to follow the procedure for a random sub-sample of just 93 units but MlWiN returns always the same error message. Can you help me to understand the nature of my problem?

Thanks in advance!

[moback]

Please check that your dataset is balanced, the AC function requires that there are no mising data.
Good luck!

[Liam]

Please check that your dataset is balanced, the AC function requires that there are no mising data.
Good luck!

But what if I checked everything and the problem is still there?

[moback]

Well, unbalanced is what is meant by 'wrong length'. Sometimes everything works out if you press 'clear' and start from scratch. Hope that works, if not I fear I can't come up with any more ideas.