A well-designed impact evaluation study in the education sector is relevant in informing decision and policymaking based on high-quality evidence generated from the research. In this paper, we provide a chronology on how we developed and implemented an impact evaluation on school facilities grant (SFG) programme designed to support Government aided primary schools in Uganda -to construct classrooms, sanitation facilities as well as teacher houses. We describe the appropriate methodology, randomization designs implemented and the target groups. Results revealed that selecting a clear intervention with identified observable and unobservable characteristics is important for the robust results. Measuring attribution on outcomes may also require a balance on internal and external validity checks and analysis. The internal validity, in addition to statistical measures also requires stakeholders' engagement in the impact study process as a way of promoting social audits of public programmes. Finally, a well-planned and designed evaluation often leads to increased public trust in the findings and evidence uptake hence informing policy decision in management of programmes and projects. 353 populated and neediest schools acquire physical infrastructure, in response to the national and international (EFAs and MDGs) commitments of universal primary education. The SFG aims at: a) promoting equitable access to primary education; b) building capacity within districts and the local communities as well as supporting supervision on sites; and c) alleviating poverty. The evaluation sought to answer the following question: Do schools that receive SFG register better learning outcomes than those that do not receive SFG? According to Khandker et al. (2010), to attribute an outcome to a particular intervention, impact evaluation should determine the instruments through which beneficiaries are responding to the intervention. In his study, education programmes usually appear promising at their outset, but with time they do not generate the expected outcomes. Therefore, in such cases conducting an impact evaluation would enable policy makers understand what works, when, where and how. This requires use of appropriate research methods.It is a universal fact that more education is associated with higher earnings with the global average rate of returns to schooling estimated at 10%. However, the positive benefits of education differs from country to another depending on factors related to gender, socio-economic status, geographical location, ethno-linguistic background among others (Montenegro and Patrinos, 2014; World Bank, 2012). The rigorous evaluation studies often isolate the factors and are able to measure attribution in the context. Well-conducted impact evaluations of programmes often lend empirical support to the various hypotheses on the education interventions needed by countries to adopt education reforms. According to Gertler et al. (2007); first, an appropriate model of behavior; second, detailed quantitative and qualitativ...