Replicate levels in alternative-specific conditional logit

[Johannes Meyer]

In my data each individual repeatedly chooses one alternative from unique choice sets/cases.

When I run asclogit on Stata 13 with

asclogit y x, case(case) alternative(alternative)

I get the error

variable alternative has replicate levels for one or more cases; this is not allowed

I believe this has to do with repeating alternatives: In some cases in my data, one alterative is the same as in several other cases, while the other two alteratives are different. I.e. each combination of alternatives is unique, such that each case is unique, but the alternatives can repeat themselves between cases.

[Johannes Meyer]

My solution: Each case has to have a unique identifier, both within and across individuals. The same is true for

asmprobit

cases and

mixlogit

groups.