Test- und Fra­ge­bo­gen­ent­wick­lung

A 120 item gc test

This is a 120 item measure of crystallized intelligence (gc), more precisely, declarative knowledge. Based on previous findings concerning the dimensionality of gc (Steger et al., 2019), we sampled items from four broad knowledge areas - humanities, life sciences, natural sciences, and social sciences. Each knowledge area contained three domains with ten items each, resulting in a total of 120 items. Items were selected to have a wide range of difficulty and to broadly and deeply cover the content domain. Items are available in German and English. The development of the inital item pool is detailed in Steger et al. (2019). We used and described the 120 item gc measure in two recent publications (Schroeders et al., 2021Watrin et al., 2021). To avoid item exposure: If you are an interested researcher, please drop me a line and I'll provide you access (schroeders@psychologie.uni-kassel.de).

A 12 item gc test (BEFKI gc-K)

There is also a ultra-short version in German, BEFKI gc-K, with a testing time of 5 min. It comprises of 12 multiple-choice items, 4 items for the knowledge areas humanities, natural sciences, and social sciences. The test construction has been described in Schipolowski et al., 2013 and Schipolowski et al., 2014. In short, it is a unidimensional gc measure that has been presented to a nationally representative sample of 1,134 German adults. For more details on reliability and validity see Schipolowski et al., 2013. Again, to avoid item exposure: If you are an interested researcher, please drop me a line and I’ll provide you access (schroeders[at]psychologie.uni-kassel[dot]de).

Ge­ne­ral Health Know­ledge (GHK-75)

The General Health Knowledge (GHK-75) is an inventory of general health knowledge across the following five domains: (a) anatomy, (b) health-promoting behavior, (c) medical treatment, (d) mental health, and (e) physical illness. A total of 75 items were sampled from a larger pool of health-related knowledge items using Ant Colony Optimization, maximizing reliability and construct coverage simultaneously. Test development and psychometric properties are described in more detail in Steger et al. (2022). In the accompanying open OSF project, we provide an English and a German version of the GHK-75 which interested researchers are welcome to use for their own studies on health knowledge.


We recently developed a psychometric sound and age-invariant short scale of the HEXACO Personality Inventory. Originally intended for longitudinal research, the HEX-ACO-18 can also be used for cross-sectional studies requiring an efficient measurement of personality. The scale development employing a combination of Ant Colony Optimization and Local Structural Equation Modeling is described in more detail in Olaru & Jankowsky (2021). In our overview of the HEX-ACO-18, we also provide information on the corresponding original HEXACO-100 item number, so interested international researchers can use the numerous available translations of the items from the hexaco.org website.