Flu Vaccine Studies: Pseudo-Randomized or Untrustworthy Results?

Brownstone Institute · Nov 5, 2026

Flu Vaccine Studies: Pseudo-Randomized or Untrustworthy Results?

by Eyal Shahar at Brownstone Institute

Preamble

The validity of a study, or a series of studies, may be questioned by several methods, one of which is identifying unexpected results. Consider the following example, which I used to teach in an introductory epidemiology course.

Having yellow-stained fingers is associated with lung cancer, but we know that the association does not reflect causality. Yellow-stained fingers do not cause lung cancer. Rather, the association is explained by smoking — a confounder — a cause of both…