Raymond Pearl

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Pearl, Raymond


Born June 3, 1879, in Farmington, N.H.; died Nov. 17, 1940, in Hershey, Pa. American biologist, demographer, and statistician.

Pearl graduated from Dartmouth College in 1899. In 1902 he received a Ph.D. degree from the University of Michigan, where he taught zoology from 1902 to 1906. From 1907 to 1918 he headed the department of biology of the Maine Agricultural Experiment Station. From 1918 to 1925 he was professor of biometry and vital statistics at Johns Hopkins University, later becoming professor of biology. In the 1930’s he taught at other universities. Pearl was president of the International Union for Scientific Investigation of Population Problems (1928–31), the American Association of Physical Anthropologists (1934–36), and the American Statistical Association (1939).

Pearl’s principal works concerned the biometry and biology of man. Studying the dependence of population growth on population density among fruit flies, Pearl established that this dependence is expressed in the form of a logistic curve, that is, at first the population growth increases, and then, having achieved a certain level, slows and ceases. Disregarding man’s social nature, he applied this law to human population growth in individual countries.


Studies in Human Biology. Baltimore, Md., 1924.
The Biology of Population Growth. New York, 1925.
Constitution and Health. London, 1933.
The Natural History of Population. New York, 1939.
Introduction to Medical Biometry and Statistics, 3rd ed. Philadelphia-London, 1940.


References in periodicals archive ?
It will assess the effectiveness of the patch in avoiding pregnancy using the Pearl Index as the primary contraceptive efficacy measure.
The implant has a length of 40mm and a diameter of 2mm and is provided in a disposable sterile inserter for sub dermal application contraceptive action is achieved mainly by inhibition of ovulation and lasts for 3 years (Makarainen et-al 1998) (2,3,4) Efficacy of this implant is excellent with pearl index of O.
The clinical trial will assess the effectiveness of the patch in preventing pregnancy using the Pearl Index as the primary contraceptive efficacy measure.