# Does 'As Good As Random' Have a rigorous definition in identification strategies?

If using an identificaton strategy such as differences in differences, Regression Discontinuities, or IV's, I see the phrase 'as good as random' used alot. Does this have a rigorous definition, or is it just another way of saying what we are trying to accomplish when ensuring exogeneity of the above estimators?

• "Does this have a rigorous definition...?" No. – Michael Aug 17 '20 at 0:12