[Limdep Nlogit List] clustering on a RP nested logit model

[Liberini Federica]

Hello,

I am trying to estimate a random parameter nested logit model, on a pooled database, where there are 19 alternatives to choose from. When using the cluster options (with command "; cluster=groupname "), I get the error message :

Error: 1081: Mismatch of # indivs. and number implied by groups
Error: 1081: Mismatch of # indivs. and number implied by groups

I should point out that the data is sorted by group first, then by individuals, then alternatives. I also tried sorting with different orders and it still did not work.
Additionally, I checked the data for any bug on other softwares (e.g. stata) and there I had no problems with the clusters.

Any idea of what could be triggering the error code?

Many thanks
Federica