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Behavioural Science

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Research Methodology

Experimental Design for the Study of Explanatory Diagnosis

Martin Metzmacher
· 1 min read

The study of explanatory diagnosis can best be conducted with an experiment, manipulating the data in a way so that an ambiguous, specific cause for mental illness is rendered more active in the mind of the clinician. This could be a for example a case about psychotic behaviour that could be attributed to a depression or dementia. One would prime either the concept of depression or dementia beforehand and see if that influences the clinicians explanation of the possible causes of the illness. In fact this poses a 2 (information data) x 2 (priming) design, that allows to test some assumptions about the process of evaluation. For example it would be interesting to see if the clinician is more likely to assimilate data if he or she has been primed with the congruent concept beforehand. The priming manipulation could be done in several ways, supra and subliminally. One ecological valid manipulation would be to have the clinician read other patients cases beforehand that have a distinct diagnosis (either depression or dementia) and see if the still active construct is carried on to the evaluation of the next patient.

Research Methodology1 min read

The Downside of the Glorious RCTs

RCTs are great and every empirical scientist loves them. Everyone? No there is a small village in the south of France…Well to be honest I believe that RCT’s are just a hype. Of course they were great in reducing a lot of statistical problems and have helped psychology to become a “respected science” and earn […]

Research Methodology1 min read

What is Effect Size?

Effect size is a parametric test, belonging to the GLM family that allows to compare the size of an effect between two groups (or for that matter two conditions in one group). The test can be used in all kinds of research designs (experimental and non-experimental) that employ different kind of measurements or/and manipulations. Given […]

Research Methodology1 min read

Why the CBCL’s Inter-rater Reliability is poor at the Item and Syndrome level

There seem to be no obvious methodological or statistical issues that could account for the poor inter-rater reliability. Embregts argues that informants might have a different view on presence and severity of behavioral problems depending on the frequency and quality of interaction they have with the client (“biased” data). Secondly both judges might have different […]