The primary purpose of developing a voters list is to separate the function of verifying voter eligibility from the balloting process. Voter registration involves certifying that a person is eligible to vote, as well as informing the person of the polling station where he or she may vote and the electoral district (if applicable) in which the vote will be counted. It is not absolutely essential to separate verifying voter eligibility from balloting, and some elections, including national elections, have been held without any voters list. However, it is far easier to manage election day activities if certification has already been completed and used to produce a voters list.

In addition to certifying that the persons listed are eligible to vote, the voters register has other uses that provide further justification for its cost. Among the areas in which it has a secondary use are the following:

• Legitimacy. Democratic elections are based on the principle of one person, one vote. For this principle to be applied, all eligible voters must have the opportunity to cast a ballot, each person must be able to vote once and only once in an electoral event, and all the votes cast must have equal value or weighting. A voters list – particularly one that scores high on the three performance measures of currency, accuracy and completeness – lends greater legitimacy to the outcome of an election by reinforcing the commitment to democratic principles.
• Districting. Electoral boundaries exist where separate geographic areas (called electoral districts or constituencies) each choose their own representatives in the legislature. One of the principles in delineating electoral districts is that they should all have equal population. Those responsible for districting may be guided by census data or data from the voters list.
• Voter education. The voter registration initiative may be a key component of a voter education campaign. Through the registration drive, the election authority comes into contact with most eligible voters. It can use this opportunity to deliver key election information, such as the date, time and place to vote. At the same time it can explain how the political system works, how elections enhance governance and why citizen involvement matters.
• Party spending. Sometimes the size of the electorate is used to determine political party spending, including the amount that parties may spend in a national or local campaign. This means that there may be a direct connection between the number of people on the voters list and the funds that a party or candidate may spend in an election.
• Party campaigning. Usually political parties are given information from the voters list for campaign purposes. A list of names and residential addresses will help them in door-to-door canvassing, distributing campaign materials and using the media to convey key messages. When going door to door, parties may attempt to identify likely supporters and then target these people in get-out-the-vote efforts.
• Citizen identification. If registration includes issuing voter identification cards with a number of security features, these may come to be used as national identification cards. Sometimes voter identification cards are of such high quality that they become the primary means of identifying citizens.
• Mark of citizenship. For newly eligible voters – that is, young people who have recently reached voting age or immigrants who have satisfied voting requirements – inclusion on the voters list is a mark of citizenship. It indicates that they have become full participants in the political community and enables them to have a say in choosing a government.
• Preparation for election day. Sometimes the voter registration drive provides an early warning of election day trouble. For example, certain political parties or groups wishing to undermine electoral legitimacy may seek to disrupt registration. Alternatively, voter registration may help the election authority gather strategic information to guide decisions on such issues as where to locate polling stations or whether to set up mobile polling stations.
• Signal of democratic progress. In post-conflict situations, the voter registration initiative is a clear and unmistakable signal that the democratic process is advancing.