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Submitted by Matt Groh on

Hi Eric,

In the context of treatment regressions for randomized experiments, the control mean is a simpler, more intuitive data point than the constant term. Ultimately, the control mean is the counterfactual for the treatment mean whereas the constant term is just a component of the regression. If a treatment regression is y=a+bT + e where T=1 for treatment and T=0 for control, then the constant term and control mean will be nearly the same. But, if a treatment regression includes stratification covariates (e.g. y=a+bT + cV + e), then the constant term may be very different from the control mean. As for a literature reference, I'd just suggest you look at examples from papers reporting on randomized experiments (e.g. Miracle of Microfinance? Evidence from a Randomized Experiment and Estimating the Impact of Microcredit on Those who Take it Up: Evidence from a Randomized Experiment in Morocco)