Countries that delimit electoral districts must designate a boundary authority and establish some machinery for carrying out the task of redistricting. The task assigned to the boundary authority is the same in all countries: divide the country into districts for the election of representatives.
The composition of the boundary authority and the degree of independence from the legislature or partisan concerns granted to this authority, however, vary considerably from country to country. Some countries allow legislators to draw their own districts. Other countries, in an attempt to remove "politics" from the process, assign the task of redistricting to an independent boundary commission. In some countries, redistricting is centralised under a single redistricting authority while in other countries, states or provinces draw their own districts, with or without a uniform set of rules. In many countries, the boundary authority is granted the power to choose the final districting plan. But in some countries with non-legislative boundary authorities, the legislature or the government must approve the final districting plan before it can be implemented.
The types of boundary authorities countries have established and the degree of independence countries have accorded these authorities cover a broad spectrum. At one end of the spectrum is the United States, where the redistricting process is very political and decentralised. The responsibility for drawing districts for the United States Congress rests individually with the fifty states. There are few limitations on the states, and the boundary authorities are almost always political entities, i.e., state legislatures.
At the other end of the spectrum are many of the Commonwealth countries, where politicians have opted out of the redistricting process and granted the authority to redistrict to neutral or independent commissions. A central agency may draw districts for the entire country. If the central agency does not actually draw the districts, it establishes guidelines for regional commissions and oversees the redistribution process. The final decision as to which district boundaries should be implemented often rests with the commission and not with the legislature.
This section will examine alternative approaches to the designation of a boundary authority. It will discuss the composition of the boundary authority, whether the authority should be partisan or non-partisan, and whether a central authority or regional authorities should perform the task of redistricting. Who has the authority to make the final decision as to which set of district boundaries are to be implemented will also be considered.