Regarding case selection, Gary King, Robert Keohane, and Sidney Verba alert from "picking around the dependent variable". They argue by way of example that researchers can not make legitimate causal inferences about war outbreaks by only investigating situations in which war did happen (the researcher must also look at cases https://hbr-case-study-writing-he00722.full-design.com/rumored-buzz-on-harvard-case-study-analysis-72611731