st: logistic and logit and test

[David Airey <david.airey@vanderbilt.edu>]

I'm more used to continuous y's so this is probably a beginner's 
question.

"Logistic" in Stata produces an odds ratio estimate, while "logit" 
produces a coefficient. The standard interpretation of the odds ratio 
estimate is it is the number by which the odds favoring y = 1 is 
multiplied, with each 1-unit increase in the x variable, with any 
covariates held constant. The logit coefficient describes the change of 
the logit or log odds of y for each 1-unit change in x, with any 
covariates held constant. If the logit coefficient were say,

.6280264

this means that the logit or log odds of y increases ~.63 for every 
unit of x. Equivalently, we could say each additional unit of x 
multiplied the odds of y = 1 by

e^.6280264 = 1.87

All this has made me wonder whether the OR test is testing whether the 
OR is different from "1", whereas the test for the logit coefficient 
really is testing the coefficient being different from 0? Since exp(0) 
= 1, this suggests as much. But my question is that use of "test x" 
after either command produces the statement that x = 0 is the test.

Why am I confused?

-Dave

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