This Assessment News article introduces readers to a statistical approach to making sense of student assessment data in order to help teachers understand whether or not changes in practice have made a difference to learning. It Worked! is the brainchild of Darcy Fawcett, HoD Science at Gisborne Boys’ High School, and Across-School Teacher for the Turanganui-ā-Kiwa Gisborne Kāhui Ako Community of Learning. In this article, Darcy explains a range of ways that schools can apply research-based methods to generate data stories which can illustrate evidence of learning. Valid assessment data stories allow teachers to more effectively evaluate, improve, and share practice. The article concludes with insights into how data stories can support teacher inquiry, including the expertise, procedures, and collaborative relationships which can help.