====== Psychometrics ======

===== What is psychometrics? =====

Psychometrics is

  * "//the field of study concerned with the **theory and technique of educational and psychological measurement**, which includes the **measurement of knowledge, abilities, attitudes, and personality traits**. The field is primarily concerned with the construction and validation of measurement instruments, such as questionnaires, tests or personal assessments.//"(([[http://books.google.com/books?id=toSzklA5PVsC|Drogin, Eric Y., Frank M. Dattilio, PhD Frank M Dattilio, Ph.D., Abpp, Robert L. Sadoff, and Thomas G. Gutheil. Handbook of Forensic Assessment: Psychological and Psychiatric Perspectives. John Wiley and Sons, 2011.]]))

Psychometrics started to develop from early works on intelligence and intelligence testing.(([[http://www.google.com/books?id=PvsNAAAAQAAJ|Gipps, C. V. Beyond testing: towards a theory of educational assessment. Routledge, 1994.]])) Intelligence was supposed to be measurable since it was fixed and observable, and later compared to fixed grades.

The measurement or assessment can take many forms like interview, examination, multiple-choice, diagnostic, practical, continuous assessment, ..., but all of these methods need be:

  * standardized,
  * valid,
  * reliable, and
  * free from bias.

Psychometrics uses two kinds of tests and test items(([[http://books.google.com/books?id=-lUFDpFtcwIC|Rust, John, and Susan Golombok. Modern psychometrics: the science of psychological assessment. Routledge, 1999.]])):

  * knowledge-based tests and test items for measuring a person's knowledge, and
  * person-based tests and test items for assessing mood, cynical symptoms, personality or attitudes.

Two important assumptions of psychometrics are:(([[http://www.google.com/books?id=PvsNAAAAQAAJ|Gipps, C. V. Beyond testing: towards a theory of educational assessment. Routledge, 1994.]]))

  * assumption of unidimensionality (meaning that the items in a test should measure only a single attribute), and
  * assumption of universality (meaning that a test score has the same meaning for all individuals anywhere).


===== Psychometrics, educational measurement and educational assessment =====

Since psychometrics was originally introduced to deal with issues of measuring intelligence, a need for an assessment approach specifically designed for educational process appeared. This new assessment process should have been useful in the processes of planing, teaching, learning and evaluation.(([[http://www.google.com/books?id=PvsNAAAAQAAJ|Gipps, C. V. Beyond testing: towards a theory of educational assessment. Routledge, 1994.]]))