The line item budget typically is used when control is the budget’s main function. It also is the budget type most cities and towns use. In a line item budget, expenditures are listed under a large subject area – a fund; then broken down by a function or purpose, such as a department; then by an object, for example, office supplies or utilities. Utilities can then be further broken down into items such as gas, water, and electricity. Imagine a tree, where you start at the trunk, then split into branches, then spread into leaves. The trunk is the General Fund, the large branches are the departments, and the leaves are all the items that will be purchased within each department. The more detailed the line items, the more control the governing body or manager has over expenditures.
According to Budgeting: A Guide for Local Governments:
"… the line-item budget originated in the late nineteenth century in response to the excesses of the political machines that controlled many state and local governments: this format was ideally suited to shifting power away from political bosses and toward legislative bodies, which were more accountable to voters."
The downside to line item budgets is they provide no information about the activities or functions of a program or department and how efficiently they operate. The focus is strictly on what is spent.