A nationwide representative sample of public schools in rural India found teacher absence rate of 23.6%. Increases in school monitoring were strongly correlated with reductions in teacher absence rates. Investing in reducing teacher absence through better monitoring could be over ten times more cost effective at reducing the effective student teacher ratio (net of teacher absence) than investing in hiring more teachers. The marginal returns to inefficiency reduction are likely to be considerably higher than the returns to augmenting school inputs in a “business as usual” manner.