All policy costings presented to the Office for Budget Responsibility at Summer Budget 2015 were scrutinised and all-but-one were certified as reasonable, central estimates. All were included in our forecasts. The Government’s Summer Budget 2015 document briefly describes the methodologies underpinning these costings. In our July 2015 Economic and fiscal outlook we have published an assessment on the level of uncertainty associated with each of the certified costings. For those identified as being particularly uncertain, we provided greater detail on the most important sources of uncertainty.