Improvement networks are a relatively recent phenomenon in US education that create interorganizational networks of educators working together to improve specific educational problems. A shared emphasis of these networks is the use of data to support the improvement process, but little is known about their data use in practice. This study takes an in-depth look at the 800+ data artifacts created and used in a single focal network's 3rd year, applying a mixed methods case study design. The findings show that while data artifacts are predominantly created to support the improvement process, they are frequently used for relationship management as network hub members navigate the sociopolitical dynamics typical of a complex change effort - if they are used at all. The study has implications for practitioners as they decide what data artifacts to create and use, as well as for researchers' theory building about productive data use in improvement efforts.