The diachronic change of word-formation patterns is currently gaining increasing interest in cognitive-linguistic and constructionist approaches. This paper contributes to this line of research with a corpus-based investigation of nominalization with the suffix -ung in German. In doing so, it puts forward both theoretical and methodological considerations on morphology and morphological change from a usage-based perspective. Regarding methodology, the long-standing topic of how to measure (changes in) the productivity of a morphological pattern is discussed, and it is shown how statistical association measures can be applied to quantify the relationship between word-formation patterns and their bases. These findings are linked up with theoretical considerations on the interplay between constructional schemas and their respective instances.