Hi Michael, many thanks for your time and the hint. This is much appreciated.
Indeed, I managed it to get part of the dataset from which I want to develop my final logit model in the correct long format with true/false standing in the column for the choice variable,. But the problem with the variable I want to define with an alternative specific coefficient (=P_id) still persists. If doing the mlogit procedure and defining the table for this variable as 1) a data frame I get the comment [Start of R quote] Error in model.frame.default(terms(formula, lhs = lhs, rhs = rhs, data = data), : invalid type (list) for variable 'P_id' [End of R quote] Btw, length of the variable/data frame P_id is 6, the length of the choice variable is 1,406 and the length of a variable with a generic coefficient (and which is working fine) is 8,436. 2) as a matrix, I get the comment [Start of R quote] Error in model.frame.default(terms(formula, lhs = lhs, rhs = rhs, data = data), : variable lengths differ (found for 'P_id') [End of R quote] Btw, length of the variable/matrix P_id is 8,436, the length of the choice variable is 1,406 and the length of a variable with a generic coefficient (and which is working fine) is 8,436. Any comment or hint (also on literature, in case my mistakes are too simple and obvious) would be helpful. Best regards, Lee -- View this message in context: http://r.789695.n4.nabble.com/length-of-variable-in-mlogit-tp4638323p4640250.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.