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
In statistics, an effect size is a value measuring the strength of the relationship between two variables in a population, or a sample-based estimate of that quantity. It can refer to the value of a statistic calculated from a sample of data, the ...
, which helped to lay foundations for current statistical
meta-analysis
A meta-analysis is a statistical analysis that combines the results of multiple scientific studies. Meta-analyses can be performed when there are multiple scientific studies addressing the same question, with each individual study reporting me ...
and the methods of
estimation statistics
Estimation statistics, or simply estimation, is a data analysis framework that uses a combination of effect sizes, confidence intervals, precision planning, and meta-analysis to plan experiments, analyze data and interpret results. It complement ...
. He gave his name to such measures as
Cohen's kappa
Cohen's kappa coefficient (''κ'', lowercase Greek kappa) is a statistic that is used to measure inter-rater reliability (and also intra-rater reliability) for qualitative (categorical) items. It is generally thought to be a more robust measure th ...
,
Cohen's ''d'', and
Cohen's ''h''.
Power analysis and significance testing
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 H
0 is false, the misinterpretation that its complement is the probability of successful replication, and the mistaken assumption that if one rejects H
0 one thereby affirms the theory that led to the test". He encouraged instead a recognition of single studies as exploratory and a reliance on
replication for support.
Career
A graduate of
City College, he received his PhD in clinical psychology at
New York University
New York University (NYU) is a private research university in New York City. Chartered in 1831 by the New York State Legislature, NYU was founded by a group of New Yorkers led by then- Secretary of the Treasury Albert Gallatin.
In 1832, th ...
in 1950.
Between 1959 and retirement in 1993 he worked in the psychology department at New York University, latterly as the head of the
quantitative psychology
Quantitative psychology is a field of scientific study that focuses on the mathematical modeling, research design and methodology, and statistical analysis of psychological processes. It includes tests and other devices for measuring cognitive a ...
group.
He was awarded the Distinguished Lifetime Achievement Award by the
American Psychological Association
The American Psychological Association (APA) is the largest scientific and professional organization of psychologists in the United States, with over 133,000 members, including scientists, educators, clinicians, consultants, and students. It ha ...
in 1997 and was a fellow of the
American Association for the Advancement of Science, the American Psychological Association and the
American Statistical Association
The American Statistical Association (ASA) is the main professional organization for statisticians and related professionals in the United States. It was founded in Boston, Massachusetts on November 27, 1839, and is the second oldest continuousl ...
.
Selected works
Below are listed some of Cohen's works. Where multiple authors are present, full names are used to facilitate reader searches for other works by those authors.
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References
External links
A Power Primer by Jacob Cohen
{{DEFAULTSORT:Cohen, Jacob
American statisticians
20th-century American psychologists
Jewish American scientists
1923 births
1998 deaths
20th-century American mathematicians
Fellows of the American Association for the Advancement of Science
Fellows of the American Statistical Association
20th-century American Jews