This entry mainly introduces the tests of vocabulary/collocation used in data-driven learning (DDL) research. DDL refers to second language (L2) learners exploring authentic language data by using corpus linguistics tools and techniques (Boulton & Cobb, 2017). A significant part of empirical DDL studies is the evaluation of vocabulary and collocation learning outcomes. Vocabulary (including collocations) tests play an important role in the study design in DDL research. Previous empirical DDL studies have mainly employed self-designed tests, multiple-choice and gap-filling questions and error corrections, with a few using established vocabulary tests. This entry aims to provide an overview of the various assessment formats used in these studies and exemplify the application of these formats in different research contexts. After reviewing the formats, it highlights their unique characteristics and draws suggestions for measuring vocabulary within the context of DDL activities. Additionally, it offers insights into potential areas for improvement in future studies.