Psychometrics is a field of study within psychology concerned with the theory and technique of measurement. Psychometrics generally covers specialized fields within psychology and education devoted to testing, measurement, assessment, and related activities. Psychometrics is concerned with the objective measurement of latent constructs that cannot be directly observed. Examples of latent constructs include intelligence, introversion, mental disorders, and educational achievement. The levels of individuals on nonobservable latent variables are inferred through mathematical modeling based on what is observed from individuals' responses to items on tests and scales.
In psychometrics, item response theory (IRT) is a paradigm for the design, analysis, and scoring of tests, questionnaires, and similar instruments measuring abilities, attitudes, or other variables. It is a theory of testing based on the relationship between individuals' performances on a test item and the test takers' levels of performance on an overall measure of the ability that item was designed to measure. Several different statistical models are used to represent both item and test taker characteristics. Unlike simpler alternatives for creating scales and evaluating questionnaire responses, it does not assume that each item is equally difficult. This distinguishes IRT from, for instance, Likert scaling, in which "All items are assumed to be replications of each other or in other words items are considered to be parallel instruments". By contrast, item response theory treats the difficulty of each item as information to be incorporated in scaling items.
Louis Leon Thurstone was an American pioneer in the fields of psychometrics and psychophysics. He conceived the approach to measurement known as the law of comparative judgment, and is well known for his contributions to factor analysis. A Review of General Psychology survey, published in 2002, ranked Thurstone as the 88th most cited psychologist of the 20th century, tied with John Garcia, James J. Gibson, David Rumelhart, Margaret Floy Washburn, and Robert S. Woodworth.
In psychology and sociology, the Thurstone scale was the first formal technique to measure an attitude. It was developed by Louis Leon Thurstone in 1928, originally as a means of measuring attitudes towards religion. Today it is used to measure attitudes towards a wide variety of issues. The technique uses a number of statements about a particular issue, and each statement is given a numerical value indicating how favorable or unfavorable it is judged to be. These numerical values are prepared ahead of time by the researcher and not shown to the test subjects. The subjects then check each of the statements with which they agree, and a mean score of those statements' values is computed, indicating their attitude.
The Rasch model, named after Georg Rasch, is a psychometric model for analyzing categorical data, such as answers to questions on a reading assessment or questionnaire responses, as a function of the trade-off between the respondent's abilities, attitudes, or personality traits, and the item difficulty. For example, they may be used to estimate a student's reading ability or the extremity of a person's attitude to capital punishment from responses on a questionnaire. In addition to psychometrics and educational research, the Rasch model and its extensions are used in other areas, including the health profession, agriculture, and market research.
The polytomous Rasch model is generalization of the dichotomous Rasch model. It is a measurement model that has potential application in any context in which the objective is to measure a trait or ability through a process in which responses to items are scored with successive integers. For example, the model is applicable to the use of Likert scales, rating scales, and to educational assessment items for which successively higher integer scores are intended to indicate increasing levels of competence or attainment.
Quantitative psychology is a field of scientific study that focuses on the mathematical modeling, research design and methodology, and statistical analysis of psychological processes. It includes tests and other devices for measuring cognitive abilities. Quantitative psychologists develop and analyze a wide variety of research methods, including those of psychometrics, a field concerned with the theory and technique of psychological measurement.
Georg William Rasch was a Danish mathematician, statistician, and psychometrician, most famous for the development of a class of measurement models known as Rasch models. He studied with R.A. Fisher and also briefly with Ragnar Frisch, and was elected a member of the International Statistical Institute in 1948.
The Academy of the Social Sciences in Australia (ASSA) is an independent, non-governmental organisation devoted to the advancement of knowledge and research in the social sciences. It has its origins in the Social Science Research Council of Australia, founded in 1942.
Patrick Colonel Suppes was an American philosopher who made significant contributions to philosophy of science, the theory of measurement, the foundations of quantum mechanics, decision theory, psychology and educational technology. He was the Lucie Stern Professor of Philosophy Emeritus at Stanford University and until January 2010 was the Director of the Education Program for Gifted Youth also at Stanford.
Malcolm Preston Skilbeck was an Australian educator who worked in educational policy analysis, curriculum, tertiary and secondary education, the teaching profession and educational innovation. Some of this work was done with the Organisation for Economic Co-operation and Development (OECD) and the United Nations Educational, Scientific and Cultural Organization (UNESCO).
Psychometric software refers to specialized programs used for the psychometric analysis of data that was obtained from tests, questionnaires, polls or inventories that measure latent psychoeducational variables. Although some psychometric analysis can be conducted using general statistical software like SPSS, most require dedicated tools designed specifically for psychometric purposes.
Benjamin Drake Wright was an American psychometrician. He is largely responsible for the widespread adoption of Georg Rasch's measurement principles and models. In the wake of what Rasch referred to as Wright's “almost unbelievable activity in this field” in the period from 1960 to 1972, Rasch's ideas entered the mainstream in high-stakes testing, professional certification and licensure examinations, and in research employing tests, and surveys and assessments across a range of fields. Wright's seminal contributions to measurement continued until 2001, and included articulation of philosophical principles, production of practical results and applications, software development, development of estimation methods and model fit statistics, vigorous support for students and colleagues, and the founding of professional societies and new publications.
Bryan Stanley Turner is a British and Australian sociologist. He was born in January 1945 in Birmingham, England. Turner has held university appointments in England, Scotland, Australia, Germany, Holland, Singapore and the United States. He was a Professor of Sociology at the University of Cambridge (1998–2005) and Research Team Leader for the Religion Cluster at the Asian Research Institute, National University of Singapore (2005–2008).
Anton K. Formann was an Austrian research psychologist, statistician, and psychometrician. He is renowned for his contributions to item response theory, latent class analysis, the measurement of change, mixture models, categorical data analysis, and quantitative methods for research synthesis (meta-analysis).
Professor Jon Charles Altman is a social scientist with a disciplinary focus on anthropology and economics. He is an emeritus professor of the Australian National University currently affiliated to the Regulatory Institutions Network (RegNet), College of Asia and the Pacific, ANU. He was the founding director of the Centre for Aboriginal Economic Policy Research (CAEPR) at the Australian National University and then a research professor there until 2014 when he retired. He is a Fellow of the Academy of the Social Sciences in Australia and an Honorary Fellow of the Royal Society of New Zealand. From 2008 to 2013 he was an Australian Research Council Australian Professorial Fellow. In late 2015 Altman moved to Melbourne to take up an appointment from 1 February 2016 as research professor at the Alfred Deakin Institute for Citizenship and Globalization at Deakin University.
Gideon Jan (Don) Mellenbergh was a Dutch psychologist, who was Professor of Psychological methods at the University of Amsterdam, known for his contribution in the field of psychometrics, and Social Research Methodology.
Robert Andrew Wilson is an Australian philosopher who has worked in Canada, the United States, and Australia. He has been professor of philosophy at the University of Western Australia since November 2019, after teaching previously at La Trobe University (2017-2019), the University of Alberta, the University of Illinois, Urbana-Champaign (1996–2001), where he was a member of the Cognitive Science Group at the Beckman Institute for Advanced Science and Technology, and at Queen's University (1992–1996).
Yves Zenou is a French-Swedish-Australian economist. He is a professor at Monash University and holds the Richard Snape Chair in Business and Economics.
Matthias von Davier is a psychometrician, academic, inventor, and author. He is the executive director of the TIMSS & PIRLS International Study Center in Lynch School of Education and Human Development and the J. Donald Monan, S.J., University Professor in Education at Boston College.
