The city budget is probably a municipality's most important work product. The budget serves a number of functions. At the most basic level it is a legal document that gives city officials the authority to incur obligations and pay expenses. It allocates resources among departments, reflecting the legislative body's priorities and policies and controls how much each department may spend. Budgets often include mission statements, goals, and objectives that convey to the citizens the vision for the future of the municipality's elected officials and let the officials communicate why they have allocated the scarce resources in the manner that they did. A budget can also be an evaluation tool, comparing commitments made in the previous year's budget with actual accomplishments.