the help for -ssm- (downloaded from SSC) says it estimates Endogenous-Switch & Sample Selection Count, Binary & Ordinal Response Regression. Then it continues: "The Switch model is a binary variable model that determines the outcome of the endogenous dummy included in the outcome model. [...] The Selection model is obtained when the outcome variable is only observed if a particular condition is met (selection = 1) and the selection dummy does not enter the outcome model."
Before reading it, I thought (please note that my statistical knowledge approximates zero) that endogenous switching and sample selection were synonyms for -heckman-, while the selection dummy not entering in the second stage described -treatreg-. Can anyone explain me?
Thanks,
Nicola
P.S. I'll NOT receive/read any email but the Digest.
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