Background: In this study, the correlation between test motivation and performance on an economic knowledge test was investigated. To this end, the economic knowledge of 1018 students in vocational schools in Germany was assessed using a standardized test, and their self-reported test motivation and interest in receiving feedback on their performance on the test functioned as indicators of test motivation. The expectancy-value model served as the theoretical basis, while this paper followed Knekta and Eklöf (J Psychoeduc Assess 33(7):662-673, 2015) and focused on invested effort in particular. Further, the number of missing values on the test was examined as a potential external criterion for test motivation. The correlation between gender and test motivation being a subject of frequent discussion in the literature, gender was incorporated as a control variable into the modeling. Methods and results: Three structural equation models of the results show that self-reported test motivation (direct indicator) and the number of missing values on the test (external criterion) correlated significantly with the economic knowledge test score achieved. Interest in receiving feedback (indirect indicator) had no significant correlation with the economic knowledge test score. However, there is a positive correlation between interest in receiving feedback and self-reported test motivation. The analyses taking into account gender show that there is no correlation between gender and interest in receiving feedback or gender and self-reported test motivation. There are, however, correlations between gender and the economic knowledge test score as well as between gender and the number of missing values. Conclusions: The findings underline the importance of a differentiated view on the assessment of correlations between test motivation and test performance. Thereby, dividing indicators of test motivation into direct (self-reported test motivation) and indirect (interest in receiving feedback) indicators, as well as taking into account the external criterion (number of missing values), in particular, were seen as the value added by this study.