A full understanding of the budget planning and preparation system is essential, not just to derive expenditure projections but to be able to advise policymakers on the feasibility and desirability of specific budget proposals, from a macroeconomic or microeconomic perspective. It is much easier to control government expenditures at the "upstream" point of budget preparation than later during the execution of the budget.
Thus, fiscal economists and general budget advisors need to know:
what is the framework in which budget decisions are made;
who is responsible for planning and preparing the budget;
what are the typical weaknesses in procedures and how can these be overcome; and
Changes in budget plans be programmed and targeted?