The effects of high-quality professional development on teachers and students: a cost-benefit analysis

Does not evaluate the feasibility of implementation This report estimates the costs and benefits of the operational policy but does not estimate the costs of implementation or take a view on the machinery that might need to be put in place to implement the policy. [...] Likewise, the impact of the study on primary outcomes (an effect size of 0.09 – 0.15 depending on the subject) is the same as the impact of high-quality CPD found in the literature review. [...] 14 The central question for the counterfactual is how much CPD will teachers do, and what will the quality be, if the CPD entitlement is not implemented? There are no obvious mechanisms present in the education system that are likely to cause the number of high-quality CPD hours to grow dramatically in the next few years, so we have assumed that there is no growth in the number of high-quality CPD. [...] The Treasury’s Green Book guidance states that ‘costs and benefits should be calculated over the lifetime of an intervention’.29 For the policy we are evaluating, the question is how long until the quantity and quality of CPD in the counterfactual catch up to the quantity and quality in the policy scenario? That is impossible to know so we use the Green Book’s default recommendation of a 10-year t. [...] However, we scale costs according to the increase in the quantity of CPD so the BCR decreases to 14.1 as the increase in costs in this scenario is greater than the increase in the benefit.