Statistical findings depend entirely on which negative cases enter the population

Evidence

It is only the comparison of the positive with the negative cases that determines the significance and the sign of the relationship. Any major change to the negative population can thus lead to radical revision of causal inferences. — Gary Goertz, Social Science Concepts, 1506

Categorization

• DEEPTHINKING: It reframes sampling from a technical nuisance into the actual engine of causal inference — the control group, not the outcome cases, decides sign and significance.
• XREF: Connects to the earlier chapter’s argument that concept structure and case-selection rules are the same theoretical act, and to Milgrom’s point that institutions define the population within which exchange happens.
• SEED: Angle: ‘The control group is the theory’ — an essay on how unnoticed choices of comparison cases silently manufacture or destroy findings across the social sciences.