There is increasing literary evidence for the design of robust formative feedback in higher education. Translation of theoretical models into practice is still evolving and much of the available evidence is based on participant perceptions rather than quantitative changes in learning outcome. Students are often dissatisfied with standard modes of feedback and their perceptions often do not align with that of teachers who feel that students may undervalue the feedback. Standard feedback tends to give limited information that focuses on the assessment product and does not engage students in learning processes. Formative feedback that has been purposefully designed to scaffold student learning is theoretically more effective, especially with closure of the learning loop. This study quantitatively evaluated the effectiveness of well-designed, fit for purpose formative feedback provided to biomedical science students on their draft assignments before summative submission. Student outcome data from feedback and non-feedback groups for the performance during an assignment, a module and the year of study were analysed using a paired t-test. Students submitting a formative draft and receiving formative feedback for their assignment achieved significantly better summative outcomes for both the assignment and module than students who did not. Educational theory of effective feedback design was put into practice and shown to positively affect educational outcome for students in this module.