Countries that delimit electoral districts must establish rules and a formal structure for carrying out the process. Because different sets of districts can produce different election outcomes, even if underlying voting patterns remain the same, the choices involved in the design of the redistricting process are important. Included among those decisions are the following:
- Who should draw the district lines?
- Who should decide on the final districting plan?
- Under what grounds should the district lines be determined?
- Should the legislature have a role in drawing the districts or deciding on the final plan?
- Should the general public have input into the redistricting process?
- How often do districts need to be redrawn?
- How long will the redistricting process take to complete?
- Should formal criteria be established for line drawers to consider? If so, what criteria should be established?
- Should the plan be subject to challenge in the courts?
The task of drawing districts must be assigned to some boundary authority. The composition of the boundary authority and the degree of independence granted to this authority vary considerably from country to country. Traditionally, legislatures have been allowed to draw their own districts. Increasingly, however, countries are turning the process over to independent commissions. This is part of an international movement to eliminate "politics" from the redistricting process.
Reforms that have replaced legislatures with redistricting commissions have also included provisions for increasing public access to the redistricting process and identifying formal criteria for commissioners to consider when drawing districts. These redistricting criteria are usually listed in the electoral laws of the country. The criteria often include factors such as equality of population, respect for local administrative boundaries and other geographic features such as natural (physically-defined) boundaries, and recognition of communities of interest.
Countries usually have not adopted redistricting criteria pertaining to the actual outcome of the redistricting process--for example, fair representation for political parties or minority groups. This is because single-member districts, used by many of the countries that delimit electoral districts, cannot guarantee results that are proportional, or even minimal, for minority political parties or minority racial, ethnic, religious or special language groups in the population. Some countries, however, have adopted special provisions designed to modify the distorting effects of single-member districts and to ensure some degree of representation for minority groups.
This section examines the choices countries have made for rules and a structure to carry out redistricting, including:
