Psychometrics or psychological testing is concerned with quantification (measurement) of human characteristics, behavior, performance, health, etc., as well as with design and analysis of studies based on such measurements. An example of the problems being solved in psychometrics is the measurement of intelligence via "IQ" scores.
Statistical methods are widely used in psychometrics. Some of the methods (e.g. factor analysis ) were developed first in psychometric research. Psychometrics uses various types of surveys and tests to obtain the primary data, and a broad spectrum of statistical methods to analyze the data. Controlled experiments and design of experiment methods are widely used in psychometrics (in contrast, say, to econometrics ).