Leo Waldemar Törnqvist (14 February 1911 – 18 April 1983) was one of the first professors of statistics in Finland. He taught at the University of Helsinki from 1950 to 1974, and developed techniques that are used in official price and productivity statistics.
Törnqvist developed an approach to creating weighted price indexes across discrete time periods using weighted averages of growth rates in prices where the weights were quantity averages across the two periods. These Törnqvist indexes are used in official price and productivity statistics in many countries.
Törnqvist bought a Commodore VIC-20 about 1981 and asked his daughter Anna's son, Linus Torvalds, to help him program it. Törnqvist wrote out BASIC language programs, and grandson Linus, aged about eleven, typed them in. "He wanted me to share in the experience [and] get me interested in math," wrote Torvalds later. These were Linus's first programming experiences. Ten years later, Torvalds began to write the Linux kernel.
The Finnish Statistical Society gives a Leo Törnqvist Award for an outstanding master's degree thesis in statistics completed in the last two years.
Leo Törnqvist’s son was the nuclear physicist Nils Arthur Törnqvist (1938–2018).
- Törnqvist, Leo in Uppslagsverket Finland (in Swedish).
- Törnqvist, Leo. 1936. The Bank of Finland's Consumption Price Index. Bank of Finland Monthly Bulletin 10, 1-8.
- Törnqvist, Leo. 1981. Collected scientific papers of Leo Tornqvist. Research Institute of the Finnish Economy. Series A. ISBN 951-9205-74-8
- "BLS aggregates inputs for its multifactor productivity measures using a Tornqvist chain index." U.S. Bureau of Labor Statistics. Chapter 10. Productivity Measures: Business Sector and Major Subsectors BLS Handbook of Methods. 1997.
- "The Tornqvist index is used in the calculation of multifactor productivity." Methodology Australian Government Productivity Commission, 2009. Viewed 11 Aug 2011.
- The Tornqvist Index as a True-Cost Index, in Food Cost Indexes for Low-Income Households and the General Population, published by the Economic Research Service, US Dept of Agriculture, TB-1872, p.7
- Robert Cage; John Greenlees; Patrick Jackman. Introducing the Chained Consumer Price Index. For presentation at the Seventh Meeting of the International Working Group on Price Indices, May 2003
- Torvalds, Linus; David Diamond (2001). Just For Fun: The Story of an Accidental Revolutionary. New York City, US: HarperCollins. ISBN 0-06-662072-4., pp. 6-7.
- Finnish Statistical Society web site.
- Hoyer, Paul & Montonen, Claus & Roos, Matts (5 September 2018). "Kansainvälinen fyysikko" [Orbituary for Nils Törnqvist]. Helsingin Sanomat (in Finnish). p. B 17.CS1 maint: Multiple names: authors list (link)