The academic literature on secondary school systems in Rwanda is fragmented with varying methodologies, making it difficult to draw comprehensive conclusions. A meta-analysis approach was employed to synthesize data from multiple studies on secondary school systems, focusing on cost and effectiveness metrics. Time-series forecasting models were applied to predict future trends based on historical data. The combined dataset revealed a significant positive relationship between the number of schools per student and overall educational outcomes (r = 0.72), with an uncertainty interval around this effect size ranging from 0.65 to 0.79. This study provides robust evidence for the importance of school density in improving educational effectiveness, offering a methodological framework that can be applied to other contexts. Based on findings, policymakers should prioritise investments in infrastructure and teacher training to enhance secondary education systems in Rwanda. Meta-analysis, Secondary schools, Cost-effectiveness, Time-series forecasting, Rwanda