Predicting L2 achievement: Results from a test battery measuring language aptitude, general learning ability, and affective factors

This chapter addresses the following questions: How, and how accurately, can the
children’s performance on a L2 English proficiency test administered around age
12 (T3) be predicted on the basis of test and questionnaire data that were collected
one-and-a-half years earlier (T1)? The analyses suggest that a fairly simple equa-
tion can predict the score at T3 on new data with an average error of 1.8 points
on a 20-point scale. This equation contains seven input variables available at T1.
This accuracy corresponds to a R² of 0.58. The seven input variables comprise
questionnaire-based affective variables, as well as aptitude measures and German
(the pupils’ school language) reading test data. Most of the heavy lifting, however,
is done by an English proficiency test administered at T1, which by itself can predict
new T3 data with an average error of 2.0 points (R² = 0.41).