Psychometric test or assessment measure psychological characteristics such as personality traits, behavioural styles, cognitive abilities, motivations etc. The word psychometric literally means psychological measurement. Thomas assessments measure a wide range of different characteristics. The definition of 'psychometric' combines the words 'psyche', meaning 'mind', as well as the word 'meter', meaning 'measure'. Therefore, a psychometric test or assessment is a tool that measures a person's psychological characteristics. For example, psychometric tests and assessments can measure characteristics such as personality traits, cognitive abilities, behavioural styles and more. There is a distinction between a psychometric test and a psychometric assessment. The main difference is that a test measures candidate maximum performance using tasks that have right or wrong answers. An assessment will typically use a questionnaire-format, asking a candidate to rate its agreement levels with certain statements.

Examples of psychometric tests include cognitive ability tests, aptitude tests, logic tests and reasoning tests. Examples of psychometric assessments include personality assessments, emotional intelligence assessments and behavioural preference assessments. Psychometric tests and assessments aim to put candidate scores or responses into context, for example comparing candidate to other people. A test or assessment that compares candidate to others is known as a norm-referenced (normative) test; how did a candidate performance or responses compare to a comparative group of people (e.g. other candidates). A self-referencing (Ipsative) test or assessment will compare candidate performance or responses to its individual performance or response patterns. A test or assessment that focuses on a very specific set of skills or knowledge is called domain-referencing. An example would be a driving test as the candidate have to achieve a pre-established level of performance and knowledge to meet set criteria.