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.”¹⁾

Psychometrics started to develop from early works on intelligence and intelligence testing.²⁾ 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 items³⁾:

• 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:⁴⁾

• 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).

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.⁵⁾