Jacob Cohen (April 20, 1923 – January 20, 1998) was an American psychologist and statistician best known for his work on statistical power and effect size, which helped to lay foundations for current statistical meta-analysis[1][2] and the methods of estimation statistics.
He gave his name to such measures as Cohen's kappa, Cohen's d, and Cohen's h. In addition to being an advocate of power analysis and effect size, Cohen was a critic of reliance on, and lack of understanding of, significance testing procedures used in statistics, especially misunderstandings of null hypothesis significance testing.
In particular, he identified the "near universal misinterpretation of p as the probability that H0 is false, the misinterpretation that its complement is the probability of successful replication, and the mistaken assumption that if one rejects H0 one thereby affirms the theory that led to the test".
[3] He encouraged instead a recognition of single studies as exploratory and a reliance on replication for support.
A graduate of City College, he received his PhD in clinical psychology at New York University in 1950.