The "industrial" side of I–O psychology has its historical origins in research on individual differences, assessment, and the prediction of work performance. This branch of the field crystallized during World War I, in response to the need to rapidly assign new troops to duty stations. After the War, the growing industrial base in the US added impetus to I–O psychology. Walter Dill Scott, who was elected President of the American Psychological Association (APA) in 1919, was arguably the most prominent I–O psychologist of his time, although James McKeen Cattell (elected APA President in 1895) and Hugo Münsterberg (1898) were influential in the early development of the field.[2] Organizational psychology gained prominence after World War II, influenced by the Hawthorne studies and the work of researchers such as Kurt Lewin and Muzafer Sherif.
Research methods
See also: psychometrics and statistics
As described above, I–O psychologists are trained in the scientist–practitioner model. I–O psychologists rely on a variety of methods to conduct organizational research. Study designs employed by I–O psychologists include surveys, experiments, quasi-experiments, and observational studies. I–O psychologists rely on diverse data sources including human judgments, historical databases, objective measures of work performance (e.g., sales volume), and questionnaires and surveys.
I–O researchers employ both quantitative and qualitative research methods. Quantitative methods used in I–O psychology include both descriptive statistics and inferential statistics (e.g., correlation, multiple regression, and analysis of variance). More advanced statistical methods employed by some I–O psychologists include logistic regression, multivariate analysis of variance, structural equation modeling,[3] and hierarchical linear modeling (HLM; also known as multilevel modeling).[4] HLM is particularly applicable to research on team- and organization-level effects on individuals.