Research Methodology, Measurement and Data Analysis
Faculty of Behavioural Sciences
University of Twente

Supervisors
Prof. C.A.W. Glas, Dr S.M. van den Berg

On March 24th 2016, Inga Schwabe defended her thesis entitled

Nature, Nurture and Item Response Theory – A Psychometric Approach to Behaviour Genetics

Summary thesis
My dissertation discusses a number of psychometric issues that require special attention in the analysis of genetically-informative data, such as data on twins. These include heterogeneous measurement error, scaling and scale transformations, and harmonization of phenotypes. It is shown how ignoring these issues can result in spurious findings of genotype by environment interactions. Multilevel item response theory models are proposed that can help solve these problems.

Project

Nurturing natural talents: the influences of family, school and teacher on the expression of giftedness for educational achievement in primary school. A twin study.
The overarching goal of this project is to study the interaction of innate talent for educational achievement with environmental factors. By using data from twins, the nature of important environmental factors will be studied and how these interact with innate talent. To this end, we develop new statistical models and methodology to 1) disentangle the correlation among environmental and biological factors, and 2) handle the confounding of ‘true’ differences in twins with differences due to measurement unreliability. The project will identify environmental factors that make twins similar in achievement, and studies how innate talent interacts with environmental factors while taking into account the correlations between talent and environment. This project consists of a unique collaboration between the Netherlands Twin Register, Cito and the Methodology group at the University of Twente.

Financed by

NWO-PROO