ANCOVA with binary covariate I am looking to run an ANCOVA with continuous outcome variable, looking at the effect of a categorical variable (race/ethnicity) and controlling for a binary covariate (treatment condition, values 0 or 1). So:

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*Can ANCOVA be used with a binary (0, 1) covariate? It seems no based on what I'm reading, but I wanted to affirm.


*If not, what analysis should be used? (If regression, please say so - I am usually a regression user but am looking to integrate ANCOVA based on a reviewer comments, and this is less my wheelhouse)

The classical ANCOVA tends to refer to using a continuous covariate. In that sense, no, you cannot run ANCOVA without a continuous covariate. However, absolutely zero theory changes when it comes to running the test of the other variable. ANCOVA is just a term used to describe a common regression hypothesis test, but regression works in much more generality.
Whether or not it is wise to call this test ANCOVA is not clear to me, but the test you would run is totally legitimate: just an F-test of a factor variable with some other variable included in the regression model but not the test.
This is one example of what I have gotten into the habit of calling a “chunk test”.
