Teachers are the single most important input to learning, and in many countries in Sub-Saharan Africa teachers' emoluments account for most of the spending on basic education (Bold et al., 2017). However, in many countries in the region teachers are poorly distributed between schools. Schools in remote areas are frequently understaffed compared to those closer to towns and large villages, reflecting a reluctance among teachers to accept postings in areas with significant hardship (Mulkeen, 2010). By contrast, schools in or close to towns and larger villages, where more facilities and amenities are available, often have more teachers than required by government standards, even where the overall supply of teachers nationwide is inadequate. An estimated 28 percent of the variation in staffing between schools in the region cannot be explained by variation in the size of enrollments in schools (Majgaard and Mingat, 2012). This represents a major source of inefficiency in public education expenditure, with significant shares of finance being spent to maintain teachers in comparatively overstaffed schools where they have limited marginal impact on learning outcomes. The impacts of these inefficiencies may be exacerbated by the need to ensure a suitable range of subject expertise among the teachers at a school.