**Econometrics** may be defined as the quantitative analysis of actual economic phenomena based on the concurrent development of theory and observation, related by appropriate methods of inference.

— Paul Samuelson, Tjalling Koopmans, and Richard Stone. "Report of the evaluative committee for Econometrica."

(**Econometrics** is) the unification of economic theory, statistics and mathematics .

— Ragnar Frisch, quoted in: Warren Page (2013)

(Kálmán's) fundamental contributions to modern system theory... provided rigorous mathematical tools for engineering , **Econometrics**, and statistics , and in particular for his invention of the "Kalman filter,"... was critical to achieving the Moon landings and creating the Global Positioning System and which has facilitated the use of computers in control and communications technology.

— NSF (2008) "The President's National Medal of Science: Recipient Details"

**Econometrics** may be defined as the quantitative analysis of actual economic phenomena based on the concurrent development of theory and observation, related by appropriate methods of inference.

— Paul Samuelson, Tjalling Koopmans, and Richard Stone. "Report of the evaluative committee for Econometrica."

Intermediate between mathematics , statistics , and economics , we find a new discipline which, for lack of a better name, may be called **Econometrics**. **Econometrics** has as its aim to subject abstract laws of theoretical political economy or "pure" economics to experimental and numerical verification, and thus to turn pure economics, as far as possible, into a science in the strict sense of the word.

— Ragnar Frisch (1926) "On a Problem in Pure Economics: Translated by JS Chipman." Preferences, Utility, and Demand: A Minnesota Symposium. 1926."