Unpacking policy instruments through a mechanistic analysis: school desegregation policies in Barcelona

The redesign of school choice policies to address school segregation has become a relatively common strategy in education systems where market mechanisms play a significant role in primary and secondary education. While an increasing number of studies have examined the impact of these redesigns on school segregation, less is known about how families and students engage with and enact such adjustments. Analysing the capacity of such policies to activate the intended mechanisms and achieve the desired outcomes is essential to understanding why school choice policy redesigns succeed or fail in addressing school segregation. Drawing on a mechanistic approach to policy instruments and a realist evaluation methodological approach, this paper examines how beneficiary families respond to key instruments of the school desegregation policies adopted in Barcelona in 2019, namely, access quotas and additional funding for socially disadvantaged students. The findings demonstrate that, while in some cases these instruments achieve the expected outcome, in others they are insufficient to change beneficiaries’ school choice patterns. Beyond the particular case of school desegregation policies, the paper underscores the potential contribution of mechanistic approaches to analyse the design and implementation of education policies.