Dear SI-PASS coördinator, Does SI-PASS really work? Is it cost-effective? These are questions you might often answer as a SI-PASS coordinator. Until now these questions have been studied with quasi-experiments in which students who participate in SI-PASS are compared to students who do not participate. Sceptics might then ask if this is not a wrong comparison. Even if you control for previous performance or motivation, there might be differences between these two types of students that you are not taking into account. This is known as 'self-selection bias'. This month a study was published in Learning and Instruction which access to SI-PASS was randomized in a large-scale field experiment in The Netherlands. The article is freely available and shows that SI-PASS significantly improves grades even with moderate attendance. The study also shows that the intervention is cost-effective and that its effects can be considered large when the costs and scalability are taken into account. Please feel free to share and use this publication to inform people about SI-PASS: Effects of supplemental instruction on grades, mental well-being, and belonging: A field experiment - ScienceDirect<https://www.sciencedirect.com/science/article/pii/S0959475… Best wishes, Izaak Dr. Izaak Dekker 0628102259 | i.dekker(a)hva.nl | KSH07a09 Kenniscentrum Onderwijs en Opvoeding Hogeschool van Amsterdam