What makes domain knowledge difficult? Word usage frequency from SUBTLEX and dlexDB explains knowledge item difficulty.

The quality of tests in psychological and educational assessment is of great scholarly and public interest. Item difficulty models are vital to generating test result interpretations based on evidence. A major determining factor of item difficulty in knowledge tests is the opportunity to learn about the facts and concepts in question. Knowledge is mainly conveyed through language. Exposure to language associated with facts and concepts might be an indicator of the opportunity to learn. Thus, we hypothesize that item difficulty in knowledge tests should be related to the probability of exposure to the item content in everyday life and/or academic settings and therefore also to word frequency. Results from a study with 99 political knowledge test items administered to N = 250 German seventh (age: 11-14 years) and tenth (age: 15-18 years) graders showed that word frequencies in everyday settings (SUBTLEX-DE) explain variance in item difficulty, while word frequencies in academic settings (dlexDB) alone do not. However, both types of word frequency combined explain a considerable amount of the variance in item difficulty. Items with words that are more frequent in both settings and, in particular, relatively frequent in everyday settings are easier. High word frequencies and relatively higher word frequency in everyday settings could be associated with higher probability of exposure, conceptual complexity, and better readability of item content. Examining word frequency from different language settings can help researchers investigate test score interpretations and is a useful tool for predicting item difficulty and refining knowledge test items.

Civic Education, Teaching Quality and Students' Willingness to Participate in Political and Civic Life: Political Interest and Knowledge as Mediators.

Civic education is generally assumed to play a key role in youth's political sophistication. It aims to equip young people with the necessary competencies and skills to effectively participate in political and civic life. However, few studies have examined the relative importance of different facets of teaching quality within civic education as well as mediating factors for fostering active citizens. The present study seeks to fill this gap by investigating how different facets of teaching quality are associated with adolescents' willingness to participate in political and civic life and how this relationship is mediated by political knowledge and interest. The study uses original data from N = 250 students (n = 152 7th graders: Mage = 12.54, SD = 0.91, range = 11-14, 45% female; n = 98 10th graders: Mage = 16.12, SD = 0.97, range = 15-18, 35% female). The findings show that not all teaching quality facets are equally important. While perceived cognitive activation and open classroom climate were positively associated with students' willingness to participate, a statistically significant association with discussions of current political events in the classroom was not found. In addition, the relationship between perceived cognitive activation and willingness to participate is fully mediated by students' political knowledge and interest. This study illustrates the relative importance of different teaching quality facets in civic education and calls for continued efforts to better understand teaching quality in civic education.