Mary A. Clem (née Mary A. McLaughlin; 19051979) was an American

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change. History On ...

, and a

human computer The term "computer", in use from the early 17th century (the first known written reference dates from 1613), meant "one who computes": a person performing mathematical calculations, before electronic computers became commercially available. Ala ...

. She was a staff member at

Iowa State University Iowa State University of Science and Technology (Iowa State University, Iowa State, or ISU) is a public land-grant research university in Ames, Iowa. Founded in 1858 as the Iowa Agricultural College and Model Farm, Iowa State became one of the n ...

, and was recognized for inventing the “zero check” technique for detecting errors.

Biography

Clem was born on October 19, 1905 in the small town of

Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...

, in Story County, western

Iowa Iowa () is a state in the Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wisconsin to the northeast, Illinois to the ...

. She completed her high school degree and found employment for several years with the

Iowa State Highway Commission The Iowa Department of Transportation (Iowa DOT) is the government organization in the U.S. state of Iowa responsible for the organization, construction, and maintenance of the primary highway system. Located in Ames, Iowa, DOT is also responsi ...

and

Iowa State College Iowa State University of Science and Technology (Iowa State University, Iowa State, or ISU) is a public land-grant research university in Ames, Iowa. Founded in 1858 as the Iowa Agricultural College and Model Farm, Iowa State became one of the n ...

as a computing clerk, auditing clerk, and bookkeeper. In 1931, she joined the Mathematics Statistical Service of the Mathematics Department of Iowa State College to work as a human computer under the supervision of George Snedecor. Although she complained that mathematics was her poorest subject in high school, she was fascinated with figures and data. Most of her work was done via

punch cards A punched card (also punch card or punched-card) is a piece of stiff paper that holds digital data represented by the presence or absence of holes in predefined positions. Punched cards were once common in data processing applications or to di ...

, both creating formulas and cards, and running accuracy checks on them. She invented the “zero check” while working in Snedecor’s lab. The “zero check” is a sum that should equal zero if all other numbers had been correctly calculated. These sums helped check for errors in computing algorithms. Clem expressed that her lack of training as a mathematician is what made her notice these sums, as they had often been overlooked by others. In 1940, Clem was advanced to be technician and chief statistical clerk in charge of the Computing Service of the Statistical Laboratory. In 1962, she transferred to the new Computation Center at Iowa State University. Clem went on the 2nd Allied Mission to Greece in 1946 as a junior statistician, and there she observed the elections. In 1952, she was a statistical consultant to the

Atomic Bomb Casualty Commission The Atomic Bomb Casualty Commission (ABCC) (Japanese:原爆傷害調査委員会, ''Genbakushōgaichōsaiinkai'') was a commission established in 1946 in accordance with a presidential directive from Harry S. Truman to the National Academy of Sc ...

Hiroshima is the capital of Hiroshima Prefecture in Japan. , the city had an estimated population of 1,199,391. The gross domestic product (GDP) in Greater Hiroshima, Hiroshima Urban Employment Area, was US$61.3 billion as of 2010. Kazumi Matsui h ...

, Japan.

Publications

* Homeyer, Paul G.; Clem, Mary A.; and Federer, Walter T. (1947)
Punched card and calculating machine methods for analyzing lattice experiments including lattice squares and the cubic lattice
" Research Bulletin (Iowa Agriculture and Home Economics Experiment Station): Vol. 28 : No. 347 , Article 1.

Biography

Publications

See also

References

Further reading