In terms of case range, Gary King, Robert Keohane, and Sidney Verba warn against "picking on the dependent variable". They argue by way of example that scientists are unable to make valid causal inferences about war outbreaks by only looking at instances in which war did come about (the researcher https://rylanrewpi.webbuzzfeed.com/30527469/5-easy-facts-about-pay-someone-to-write-my-ivey-case-study-described