At a time when public expenditure is undergoing change to accommodate new needs, this report studies the impact of four institutions of the budget process upon re-allocation:  medium-term expenditure frameworks, rules of budgetary discipline, the Minister of finance, and programme review.  It develops a micro-economic classification of public expenditures and gives insight into the shifting pattern of central government expenditure in the last 20 years in 12 selected OECD countries on the basis of that classification.