Data held on a voter register can essentially be divided into two kinds: data related to persons and data related to geography. The geographic base of a voter register is a key element of the register.
The geographic base of a voter register can be used for a wide variety of functions. These include:
- recording the address of a voter on the register
- determining and recording the boundaries of electoral districts
- determining and recording which electoral districts voters are assigned to
- recording lists of habitable and non-habitable addresses (to ensure that voters do not fraudulently enrol for non-existent or non-habitable addresses)
- identifying cases where too many people are enrolled at an address (in order to identify fraudulent or out-of-date entries on the register)
- enabling targeted reviews of the register (by identifying addresses where no persons are registered or addresses with high turnover)
- facilitating reviews of the register (by producing outputs such as lists of names and addresses in street order to facilitate visits by review officers, or the mailing of review letters)
- producing lists of addresses in a variety of electronic or printed form for non-electoral purposes (such as mailing lists for other organisations or for verification of geographic bases held by other agencies)
- There are several different ways in which geographic data on a voter register can be stored depending on the type of voter register.
Name based voter registers
A voter register does not need a separate geographic base (consisting of files containing geographic data only) in order to be functional. A geographic base for a voter register could simply consist of the sum of addresses recorded for each voter on the register. This kind of register can be called a “name based” register, where addresses are contained as fields in records devoted primarily to individual persons (that is, one record per person).
A name based register, however, is an inefficient way to store geographic data. As most addresses usually contain more than one person, a database that stores address data under individual persons' names will contain many repetitions of addresses. Where many thousands or millions of names are stored, this practice will dramatically increase the size of data files and decrease the performance of computer systems accordingly.
A name based register also deprives an election management body (EMB) of the functionality of a combined list of addresses. Such a list can be used to identify anomalies, such as incorrect addresses and fraudulent registrations. It is also difficult to use a name based register to perform other electoral tasks based on addresses, such as redrawing of electoral district boundaries and reviews of the voter register.
Address based voter register
An “address based” voter register generally records addresses in a separate database file (or files) from the list of voters' names. A unique code is assigned to each unique address, and this code is used to link the list of addresses with the list of names on the register.
This approach has several advantages. It dramatically reduces the size of the files contained in the register, as each address only has to be listed once. (With a name based register, each address is repeated for as many people are registered at that address.) Assuming the address register is accurate, it should ensure that voters are registered for valid, habitable addresses. It also facilitates a range of other electoral tasks based on addresses, such as redrawing of electoral district boundaries and reviews of the voter register.
Geographic Information Systems (GISs)
The simplest form of geographic base is a relatively simple text file showing a list of addresses. This could take the form of a list contained in a name based register (see above) or a more useful address based register.
A Geographic Information System (GIS) is a more complex software product that combines text files of addresses with other geographic and spatial data such as maps, aerial photographs, building plans and “spot on the Earth” coordinates.
Developed originally in the early 1960s, GISs are computer-based tools for mapping and analysing data that contain a spatial component. GISs allow users to integrate information, create maps, visualise scenarios and solve complex problems that have a geographic element to them. GIS technology has been applied to a wide variety of enterprises, including environmental and natural resource management, infrastructure planning for transportation and utilities, governmental services and resource allocation, and military and defence planning.
GISs have several different applications for electoral purposes, particularly for drawing or redistricting electoral boundaries.
Geographic data collection and administration
A geographic base is only as good as the data it contains. The data used by an EMB will depend in large part on the data available in that jurisdiction. Some countries will have well resourced government or commercial organisations responsible for collecting and computerising geographic data. EMBs may be able to make use of these resources, if they are available. If these resources are not available, an EMB may have to develop its own collection of geographic data.
An EMB can develop a rudimentary geographic base by extracting addresses from its voter register as submitted by the voters themselves. Depending on the completeness of the voter register, this may be a good start. However, a geographic base derived solely from addresses submitted by electors will have several drawbacks. It will not be complete, as it would be unlikely that persons would be registered for every habitable address, even in countries where registration is compulsory. It is likely to contain errors, as voters often do not use the correct or “official” address of their residence when completing their registration forms. (For example, it is common for people to list unofficial place names as their local address, with the result that voters can give varying unofficial addresses for the same official address.) Perhaps most importantly, it will not be possible to use such a geographic base to determine whether an address shown on a voter registration is fraudulent, since there is no way to independently assess whether an address is accurate.
In some countries it will be possible to obtain or buy a comprehensive geographic base, or a series of them, from other government or private organisations. Local government authorities are often good sources of geographic data. These data sources can be combined into one geographic base for use for electoral purposes. Combining geographic data from a range of organisations can be a complex process. Using defined standards of geographic data is one way to reduce the complexities, but even then differences in use of names of addresses and variation in address numbering schemes can make combining of geographic data a time-consuming process.
Software can be helpful in this regard. Programs can be obtained or developed that will use matching techniques to search for duplicates and identify anomalies.
It may be necessary to conduct fieldwork to compile an accurate geographic base. Staff can be employed to travel around a jurisdiction to ascertain whether addresses listed from the geographic database are accurate, and to identify any missing addresses. The results from the fieldwork can then be entered into the geographic database.
After a geographic base has been established, it will need ongoing maintenance and administration. The data held in a geographic base will need to be updated regularly, as new dwellings are built and old ones demolished. Addresses also change when houses, flats or apartments are subdivided or added to. An EMB will need to keep abreast of changes to addresses by receiving details of changes from responsible government authorities, where possible.
In some cases, the first notice an EMB will receive of a new address might be when a voter attempts to register for the address. In these cases, the EMB will need to investigate the accuracy of the claimed address and attempt to verify it with the appropriate authority.
Geo coding and geo referencing
Every “spot on the Earth” can be defined in terms of geographic code, or “geo code” or “geo reference”. The most common such geo code is latitude and longitude. Several standard geo codes exist. An EMB can consult its appropriate government mapping authority to determine the standard geo code used in its jurisdiction.
Every address in a geographic base can be assigned a geo code. This is a useful practice as it can be used to facilitate data matching of addresses with other organisations that use the same geo code. It can also be used to plot addresses on maps and to allocate voters to electoral districts by calculating the geo codes encompassed within each district.
Geographic Positioning Systems (GPSs)
Geographic Positioning Systems are devices that can plot the precise location of the user, using satellite transmissions to define a “spot on the Earth”. For an EMB's purposes, GPSs can be used by field workers to determine the spot on the Earth of addresses for the purpose of geo coding addresses in a geographic base.
Special address categories
A geographic base used by an EMB needs to be able to allow for special address or voter categories.
Non-habitable or invalid addresses should be identified in a geographic base, to ensure that voters do not fraudulently register for such addresses and to ensure that the geographic base is complete and without any unexplained gaps. Such addresses could include parks, cemeteries and golf courses. Shops, factories and industrial areas may not generally be habitable addresses, but EMBs should be aware that such addresses may still be habitable, since owners, employees or caretakers may reside in them.
While most habitations will be houses, apartments and flats containing relatively small numbers of people, some habitations may legitimately show many people entitled to be registered at the one address. These include institutions, hospitals, universities, military bases, dormitories and prisons. EMBs will need to be aware of these types of habitations and take account of them when using software to identify addresses that appear to have too many voters registered at them.
Geographic bases will also need to account for vacant dwellings, including dwellings where no one resides and dwellings that are vacant in the sense that no persons are registered at them. For the purposes of reviewing the accuracy of the voter register, vacant addresses can be targeted to ascertain whether anyone should be registered at those addresses. It is generally desirable to include vacant addresses in the geographic base so that they can be identified as valid addresses should a person apply to be registered at that address in the future.
Special voter categories
A comprehensive voter register will be able to cope with voters who do not have addresses that fit neatly in a geographic base. Depending on the applicable electoral legislation, voters may be able to register without having a permanent address. These categories of voters might include homeless people, itinerant people who move frequently and have no permanent resident, and those people living outside the country or district who retain an entitlement to be registered. These categories of people will need to be assigned a notional geographic attachment with a particular constituency, to enable their eligibility to vote for a particular district to be ascertained.
Linking addresses with electoral districts
A geographic base will be capable of linking voters' addresses with electoral districts. This will enable the production of lists showing eligibility to vote for particular districts as well as facilitate the redistricting process.
When electoral boundaries are altered by redistricting, a process needs to be in place to update the register to reflect the new boundaries.
Addresses can be linked with electoral districts by assigning each address with a “spot on the Earth” indicator such as geo code, and defining each electoral district in terms of the “spots on the Earth” or geo codes included within it.
Where a unique geo code is not available for each habitable address, addresses can be linked to electoral districts by assigning each habitation to a small geographic unit, such as a census tract or a municipal authority district. Electoral districts can then be defined in terms of the smaller geographic units they contain in order to allocate habitations to them.
When taking the approach of using small geographic units such as census tracts to assign habitations to electoral districts, care needs to be taken where an electoral district boundary divides the geographic unit. In these cases, an EMB will need to determine on which side of the boundary each habitation is located in order to decide which electoral district should be assigned to the habitation. In some cases, this can be done using maps; in other cases a field inspection might be necessary.
