Small pilot programs often have much larger effects than programs taken to scale. I discuss reasons why, through an example of home visits for early childhood development, and then look at when larger programs may have bigger effects.
David Autor, David Figlio, Krzysztof Karbownik, Jeffrey Roth, Melanie Wasserman Public education is fundamental to providing equality of opportunity for students of different socioeconomic backgrounds. Yet, in many countries, the widespread problem of teacher sorting (Jackson 2009, Pop-Eleches and Urquiola 2013) threatens this role. Low-income students are more likely to attend schools with less qualified teachers, exacerbating potential achievement gaps (Sass et al. 2012, Thiemann 2018). Reducing teacher sorting is very relevant for equity purposes. Teachers have a significant effect on students’ test scores (Rivkin et al. 2005), absenteeism, and school suspension (Jackson 2018), as well as long-term outcomes such as college enrolment and employment. Importantly, teachers’ impact is larger among low-performing and low-income students (Aaronson et al. 2007, Araujo et al. 2016). Yet, disadvantaged schools experience more severe shortages of teachers and often fail to attract higher quality professionals (Bertoni et al. 2021). The lack of high-quality teachers in more vulnerable schools has serious implications for inequities in education.