The doctrine of evidence-based medicine was proposed in a paper in 1992. The Cochrane Collaboration was founded in 1993 and over time made meta-analysis authoritative papers.

The Student's t-test paper was published in 1908 and in the 1920's the statistical signifiance as measured by t-test wasn't central to science the way it is today.

In 1920 Freud was considered doing scientific psychology. As far as I know the General Semantics community is like the Freudian community in the regard that they didn't try to back up specific interventions in controlled trials.