1 minute read
2.5 Methodology
from Learning In Lagos
by NewGlobe
2.5.1 Descriptive Statistics
We begin by comparing average (mean) values across types of school, looking at student learning, household characteristics, teachers and teaching, and school management. Visual analyses and statistical tests provide an initial indication on whether differences across groups are practically meaningful and statistically significant.7 This descriptive analysis does not control for factors that may confound the associative patterns.
2.5.2 Correlation analysis
Next we look at correlations between the different measured factors and student learning, in an Ordinary Least Squares (OLS) regression framework. Literacy and numeracy outcomes are the dependent variables, and household, teacher, and school factors are explanatory variables. The magnitude and statistical significance of the coefficients associated with these explanatory variables provide an indication of whether any descriptive association detected is still apparent when controlling for other potentially confounding pupil-, teacher-, and school-level factors.
These regression analyses are implemented for Bridge, private, and public school samples separately so as to determine the magnitude and significance levels of any detected correlation between explanatory variables and learning outcomes separately on the sub-sample of pupils studying in the different school types.
2.5.3 Coefficient stability methods
Third, we examine the size of the correlation between school type (Bridge, private, or government) and student performance, and make some initial statements about how much of this correlation may be confounded by student family background, and what remaining difference may be a causal effect of schools. We approach this using the “coefficient” stability method outlined in by Oster (2016). This method compares the correlation between school type and student performance with and without controls for confounding factors. We then make some assumptions about the likely size of unobserved confounders, to place some possible bounds on the causal effect of schools. This method is described in more detail alongside the results in Section 3.4.
7 Tables will present estimates and standard errors by group, while graphs will include confidence intervals.
