The present article considers the association between formative and summative assessments, or assessment for learning and assessment of learning. Using data from 14 physics courses in a pre-university science program from winter 2013 to winter 2017 (N = 470), we sought to understand whether outcomes of formative assessment were related to the outcomes of summative assessment. The findings reveal a strong association between formative assessment (unit tests average) and summative assessment (final exam) and final grade, and indicate that the unit tests are strong predictors of final exam scores and final grades. However, there was only a significant, albeit small, effect between test 1 and final exam. While providing evidence that formative assessment techniques are a good indicator of how well students will perform overall, it is unclear that the unit tests contribute to improving student performance. Thus, unit tests alone appear insufficient to improve performance; students must also be provided with the means and the guidance to properly apply the feedback to improving their performance.