Thomas’ Behaviour assessment achieves reregistration with the British Psychological Society |

The Thomas Behaviour assessment, or PPA as it’s also known, has a great legacy. Based on William Moulton Marston’s original works, the assessment we offer today was first developed by Thomas Hendrickson over 40 years ago. For our company, taking the name of an influential academic demonstrated our commitment to robust science right from day one. The assessment was first registered with the British Psychological Society (BPS) in 2003, when they audited it against their technical criteria and subsequently granted it certification. 

Since then, a lot of work has been done to modernise the assessment as well as update it with contemporary psychometric approaches. In 2015, we partnered with the Psychometrics Centre at the University of Cambridge to explore ways of improving the assessment whilst maintaining the essence of it that had proven so insightful for clients around the world. New question banks were systematically created and empirically tested. Further research ensured questions were translatable into other languages, understandable to most people and balanced how positive a question’s four words sounded to people.

This research was taken further in 2019 by our in-house psychology team, who were able to replicate the initial findings on larger research samples, in order to develop a new Behaviour based assessment. Employing an improved scoring algorithm, this new version was even more reliable, meaning the insights gleaned from it would be even more accurate than with the previous version. Follow up research then ensured the assessment was valid, and that the results correlated with many work outcomes, such as performance, retention, engagement and burnout.

One particular new study found strong correlations between people’s behavioural fit to their job and not only their performance in their role, but also in their ability to support their organisational, social and psychological environment at work. We were also able to demonstrate that none of the new questions biased any particular gender or ethnic group. Fairness in testing is something that is close to the heart of Thomas and is a priority in any new research programme we embark on. 

Following all the improvements made to the science behind the assessment and the growing body of research evidence, late in 2020, we were keen to seek recertificate from the BPS and began the process of resubmission. The BPS is a member of the European Federation of Psychologists’ Associations (EFPA), who publish and maintain guidelines for evaluating the quality of psychometric assessments.

The 72-page guidelines detail exact technical criteria that an assessment needs to be able to demonstrate in order to be considered valid, reliable and fair. This was a mammoth undertaking for the team, which took around a year to complete and culminated in hundreds of pages of research evidence, technical write ups and reports. Following an extended review process by expert academic test reviewers, I’m very proud to announce that on 17th May 2022 the BPS recertified the Behaviour assessment.

Having BPS registrations allows our clients to trust in the science behind the Behaviour assessment, that it is high quality, accurate and appropriate for use in an occupational setting. The Thomas Behaviour, or PPA assessment isn’t the only one of our assessments that has been certified by the BPS. In addition to Behaviour, our Aptitude (GIA) and Emotional Intelligence (TEIQue) assessments are also certified, with the Personality assessment (HPTI) currently under review. 

If you’d like to learn more about our science, or how we could help you to make smarter, more objective people decisions, please do get in touch today