The Origins of the PST‑R
How an inexplicable discrepancy between two established test instruments led to a new understanding of personality — and, from that, to the PST‑R.
The starting point
The author of the PST, Univ. Prof. Dr Michael Dieterich, had been engaged with the concepts of “occupational maturity”, diagnostics and assessment since his doctoral thesis. Discussions with his students made one thing clear: the “snapshot” provided by existing test instruments could only ever be one aspect of counselling.
In addition, the then Institute of Practical Psychology in Zurich was repeatedly asked whether test results could be improved through targeted development programmes. A test that only describes but does not develop falls short — this thought became the guiding principle.
A contradiction that wasn’t one
In practice, Dieterich regularly found inconsistent test scores: again and again there were people with pronounced scores in contact orientation in the 16 PF and at the same time high scores towards introversion in the EPI. In the same way he discovered differences between the emotional resilience of the 16 PF and stable emotionality in the EPI.
The case study: the radio journalist
A popular radio journalist suffered from mounting strain, with sleep problems and depression. As a well-known broadcast journalist he delivered lively, well-loved programmes — yet after work his family often experienced an exhausted father at home.
In the 16 PF he scored high on contact orientation — matching the widely known image of the popular journalist. In the EPI, however, he showed a strong introversion. The interviews made it clear: outwardly he displayed a character trait (sociability) that had no counterpart in his basic structure (introversion).
Dieterich suggested he accept exactly that: to rest a little first after work, do some relaxation exercises and only then chat with his wife and children — which led to an immediate improvement in his condition.
Personality has layers
Dieterich traced the discrepancies back to the fact that the 16 PF describes more outwardly visible characteristics — the character traits — while the EPI depicts more hidden and more stable characteristics: the basic structure.
Character traits
- Clearly visible — they shape the outward impression
- Easier to change: steep learning curve, quick learning progress
- Captured in the PST‑R as 16 character traits
Basic structure
- Hard to perceive from the outside
- More stable — change requires greater learning effort
- Inherited or acquired in early childhood
Deep structure
- The oldest characteristics — from earliest childhood and/or with larger inherited components
- Very stable: a flat, saturated learning curve, hardly any change possible
- Concepts from depth psychology (Riemann, Adler)
The differing stability of personality characteristics can be explained: some personality characteristics are inherited and therefore very stable; some are shaped by earliest experiences and individual processing and are similarly lasting and stable as the inherited components.
Characteristics that emerged from middle and more recent development arose through learning processes (motivation and socialisation) and are not as lasting and stable as the potential acquired earliest.
From the PST to the PST‑R
The layer insight became a test instrument — and the revision to the PST‑R added further building blocks.
16 character traits, 5 global factors
A further factor analysis yields a summarising description of the 16 character traits through 5 global factors — roughly comparable to the “Big Five”. The global factors are the “summary”, the 16 character traits the “details”.
The openness scale
The openness scale (also known as the “lie scale”) describes how openly the questions were answered — for instance whether only socially desirable answers were given. In the PST‑R form it follows the 16 character traits and provides indications of how well the results can be evaluated.
Basic structure without judgement
The two variables of the basic structure correspond to the “Big Two” from the FPI and EPI: introversion (introverted vs. extraverted) and psychological flexibility (flexible vs. stable). In pursuit of neutral terminology, Dieterich deliberately replaced the original term “neuroticism” with “psychological flexibility” — and for both poles he formulated descriptions that distribute positive and negative remarks evenly.
92 new questions for the deep structure
Dieterich had to develop the 92 deep-structure questions entirely from scratch, as neither the literature nor existing test instruments offered an approach compatible with the developmental diagnostics of the PST‑R. He drew on depth-psychological approaches by Riemann, which were influenced by Jung and Adler.
New in the PST‑R: locus of control
The revision from the PST to the PST‑R added locus of control. The background: a person reacts to situations on the basis of their prior experience, expectations and goal for action. In 1982 Rotter distinguished the internal locus of control (control over the link between action and outcome is seen within one’s own person) from the external one (it is seen outside one’s own person).
Tested against quality criteria
The PST‑R meets the classic quality criteria of psychological diagnostics: validity, reliability, objectivity, norming, as well as economy and utility.
Get to know today’s PST‑R
Layer model, global factors, fields of application and process — everything about the PST‑R in its present form.