st: ## Interaction syntax

[Robin Jeffries <rjeffries@ucla.edu>]

I was under the impression that for a categorical variable 'wave' with
3 levels (0, 1, 2)
and another binary indicator variable 'group' (0,1) then the following
statements are the same:


1) xtlogit i.wave##i.group (other covar)

2) xtlogit wave1 wave2 group wg1 wg2 (other covar)

where wave1, wave2, wg1, wg2 are the manually created indicators and
interactions for wave and wave*group respsectivly


For most outcomes I am using this with, they produce the exact same
results. However there have been some instances where using the second
method results in a model that won't converge, but the first will.

Is there an explanation for this?

Thanks,
Robin Jeffries
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