In 1921 Frisch received a fellowship from the university which enabled him to spend three years studying economics and mathematics in France and England. After his return to Norway, in 1923, although the family's business was having difficulties, he continued his scientific activity, feeling that research, not jewellery, is his real calling. He published a few papers in probability theory, started teaching at the University of Oslo in 1925 and, in 1926, he gained his Ph. D with a thesis in mathematical statistics.
Also in 1926, Frisch published an article outlining his view that economics should follow the same path towards theoretical and empirical quantization that other sciences, especially physics, had followed. In the same year, he published his seminal article "Sur un problème d'économie pure" starting the implementation of his own quantization programme. The article offered theoretical axiomatizations which lead to a precise specification of both ordinal and cardinal utility, followed by an empirical estimation of the cardinal specification. Frisch also started lecturing a course on production theory introducing a mathematization of the subject.
Frisch received a fellowship from the Rockefeller Foundation to visit the United States in 1927. There, he looked for other economists interested in the new mathematical and statistical approaches to economics, making contacts with Irving Fisher, Wesley Clair Mitchell, Allyn Young and Henry Schultz. He wrote a paper analyzing the role of investment in explaining economic fluctuations. Wesley Mitchell, who had just written a book on business cycles, popularized widely Frisch's paper which was introducing new advanced methods.
Although his fellowship was extended to travel to Italy and France, the next year Frisch had to return to Norway because of his father's death. He spent one year to modernize and recapitalize the workshop by selling family assets and to find a jeweller to manage the business for him. Then he returned to academic work, in 1928 being appointed Associate Professor in statistics and economics at the Oslo University. In 1927 and 1928 Frisch published a series of articles on the statistics of time series. In 1929 he published his first important essay on econometric methodology, "Correlation and scatter in statistical variables", followed in the same year by "Statics and dynamics in economic theory", which introduced dynamics in economic analysis.
Frisch became a full Professor at the university in 1931. He also founded at the university the Rockefeller-funded Institute of Economics in 1932 and became its Director of Research.
Frisch married Marie Smedal in 1920 and they had a daughter, Ragna. His granddaughter, Nadia Hasnoui (Ragna's child), became a Norwegian TV personality. After his first wife died in 1952, he remarried in 1953 with childhood friend Astrid Johannessen.
Ragnar Frisch received the Antonio Feltrinelli prize from the Accademia Nazionale dei Lincei in 1961 and the Nobel Memorial Prize in Economic Sciences in 1969 (awarded jointly to Jan Tinbergen) for "having developed and applied dynamic models for the analysis of economic processes".
Frisch's most important hobby was bee-keeping. In it, Frisch undertook genetic studies.
There is a bibliography of Frisch's wrtings up to 1960 in
and there is a collection of selected essays