The seminar will offer the opportunity to discuss policy evaluation through a realistic approach. Why is science policy hard to evaluate and how can the critical realism offer some solutions? Empirically, the seminar will bring forward the findings of the research carried out when evaluating the highly reputational Spain’s performance based institutional funding programme, the “Centres of Excellence Severo Ochoa”, and it will discuss how to bring into the public employees’ identity, the researcher’s one.