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Three reasons to trust psychometrics


Most of us have taken personality tests for a job application. However, few people realise that psychometrics, the science behind them, is a robust academic discipline with a heritage going back to one of the finest scientific minds of the 19th Century.

Psychometrics is much more than a recruitment tool. It is the measurement and quantification of psychological processes, from personality factors and cognitive abilities to cultural values etc. It is premised on the understanding that human behaviour is measurable and predictable.

Researchers have laboured for many decades to create a reliable means of measuring psychological patterns. Psychometrics has evolved as an empirical, data-driven science able to model human behaviour.


Reason 1: Established Science

This is not a new area of study. The Psychometric Society, which advances quantitative methods in behavioural science, was founded in 1935. The origins of the science can be traced back much further, to the 1860s and the work of Sir Francis Galton, half-cousin and friend to Charles Darwin.

Today, a large research community is engaged in the discipline, producing a growing body of highly credible scientific evidence to support the use of psychometrics across various sectors. Universities have entire research labs dedicated to psychometrics and quantitative psychology. Such institutions include The Psychometrics Centre at the University of Cambridge, which researches the measurement of human behaviour using pioneering techniques and diverse sources of data. Psychometricians research the development of classical paper-pencil questionnaires and computer adaptive tests. More recent research has focused on the use of digital footprints to predict psychological traits.


Reason 2: Rigorous Testing and Development

Psychometricians follow a rigorous scientific process, undertaking detailed statistical analysis and meeting numerous stringent evidential criteria to prove that tests are both valid and reliable.

Some tests, like the International Personality Item Pool (IPIP) scales which measure respondents against the Big Five personality scale (also known as OCEAN, for Openness, Conscientiousness, Extraversion, Agreeableness and Neuroticism), have evolved through constant testing over decades. For example, the IPIP Neuroticism, Extraversion, Openness Personality Inventory (NEO-PI) assessment has been revised for well over 30 years across various populations and in many language versions.

Psychometric test construction includes:

  • Item development procedures are designed to confirm the relevance of each question in a test and eliminate bias. They follow an iterative process and can sometimes take years.
  • Validity assessments assess the effectiveness of the test in measuring what it was designed to measure (or not). E.g. Concurrent validity examines the accuracy of the test in predicting related future outcomes, such as the accuracy of a cognitive ability test in predicting academic outcomes.
  • Reliability analyses assess the stability of the test through retesting procedures.
  • Standardisation and norms allow test results to be comparable across different populations, where necessary and possible. Usually published tests are revised when new data becomes available.

A further challenge is ensuring that psychometric assessments safeguard against inauthentic results, whether attempts to game the system or provide answers preferred by the assessor. Attention checks can help by looking for patterned responding or measuring response times for different questions. Inconsistency in test responses is generally an indicator that the test responses are not an accurate representation of the individual, whether due to subconscious biases or fraud, at a more conscious level.


Reason 3: It Works

Well-established research confirms that these tests can be applied across many fields. In education, for example, measuring aptitude has proven to help students reach their full potential. In recruitment, the all-round objective view of a candidate’s suitability allows employers to relate applicants’ cognitive ability score to their work performance, or their integrity score and likely absenteeism as an employee.

 More recently, digital footprints have been used to accurately predict a range of insightful attributes. Researchers used Facebook ‘Likes’ to predict the extent to which a person is naturally organised, reliable, and consistent; or one’s predisposition for depression; amongst a range of other features.

If as many say, the modern age is the information age, then expect to see a lot more psychometrics in the future. While most data sources tangentially capture an aspect of human behaviour, modern psychometrics provides the whole picture.


Practical Usage

Advancement in this field has not been achieved solely within academia. Commercial entities are driving the use of psychometrics in the pursuit of profit in ways that go beyond the recruitment of staff.

Investment firms are using these tests to establish the risk a customer is willing to take to make better investment selections. While in credit risk, lenders are turning to psychometrics to help them augment traditional credit scoring methods as they find that integrity and conscientiousness (for example) are closely linked to a person’s willingness to prioritise debt and thus avoid financial difficulty.

In a world in which communication is increasingly targeted to precise demographics, some commercial adopters use psychometrics to ensure a close personality fit between their customers and their products.

It is an exciting time in the field of psychometrics. The science is evolving fast, new data sources are opening up and the practitioners themselves are constantly refining their instruments. Some people are quick to dismiss psychometrics but it is a real science broadening our understanding of people and their behaviours.