Key Issues in National Population Census planning
Key considerations
Different countries are likely to attribute varying importance to the tasks involved in planning for a census, according to their circumstances, resources, and political drivers.
Costs, sound project management, legal frameworks and publicity are all significant issues that should be considered when planning a national population census.
It is likely that cost estimates for the entire census project will be needed for legislative or governmental approval. A detailed timetable of all the activities in the form of a project plan, highlighting the major milestones and the critical path will also be required, along with some legislative provision to cover matters like confidentiality of information.
The enumerated population
Consideration needs to be given to how the population is to be enumerated, or counted. For example: is the population to be enumerated that which was resident on the night of the census (census night), or that which is usually resident, or both?
Consideration should also be given to non-nationals and how special populations are to be enumerated. For example: the hospitalised, prisoners, temporary visitors and nationals travelling abroad.
Seven steps to census planning
Census projects can typically be divided into the following seven key phases:
1. The stakeholders’ requirements – what information needs to be collected
2. Preparation including:
- i) geographic mapping – including agreeing the enumeration areas
- ii) designing appropriate forms to capture the required data
- iii) the selection and training of enumerators
- iv) running tests to ensure the processes work effectively and the timelines can be met
3. Enumeration – gathering the census data
4. Processing the census data – this might involve scanning of completed census forms
5. Census data evaluation – assessing and correcting the data
6. Analysis of census data – what has been learnt?
7. Dissemination of census data – what data will be shared with whom and how?
1) The stakeholders requirements
Consultation programmes need to be established at the very beginning of census planning to identify what data needs to be captured. The various stakeholders might include central and local government, academic researchers and the business community.
2i) Preparation - geographic mapping
The entire territory needs to be mapped using physical maps or GIS (Geographical Information Systems) software. These need to be of a sufficiently large scale such that the country can be divided into enumerator workloads using easily-observable features on the ground, like roads and rivers, without any gaps or overlaps.
The size of enumerator workloads will depend on the methods of data collection, the number of enumerators to be used and the length of the collection period.
2ii) Preparation - designing forms to capture the data
In most countries censuses are undertaken by enumerators conducting face-to-face interviews. Some countries drop-off forms and collect them at a later date. Some, more developed countries rely on postal services to distribute and return forms. These factors have important implications on the content and design of forms. It is important not to overload the form with so many questions that the quality of data captured is compromised.
Face- to-face enumeration interviews have the benefit of improving data quality and increasing the number and complexity of questions that can be included, albeit they are likely to be more costly than approaches that do not require face-to-face contact.
In general, best practice suggests that forms should be simple, should ask the fewest questions possible and lack any complex definitions, concepts or complicated routing instructions.
The same form does not have to be used for all households – a sample of households can be asked extra questions. Many countries use this short-form / long-form approach.
2iii) Preparation - selection and training of enumerators
Recruiting the large number of temporary staff needed will be a significant undertaking. The skills that the enumerators need will define the criteria for their recruitment selection. Some countries choose to select on professional qualifications, whereas others might choose to recruit from the student population.
Learning from previous census projects will help to refine the effectiveness of the recruitment process but financial constraints can be a limiting factor.
Training is usefully undertaken close to the census date, so that the knowledge is fresh in everyone’s mind. It is essential that all staff are trained to the same standard and to follow the same methods.
One popular approach is to use cascade systems for recruitment, training and general people management. This involves appointing several high level census supervisors, each of whom is responsible for a large area of the country. These then recruit and train census officers, who in turn recruit, train and supervise the work of the enumerators.
To cover ‘drop-outs’, reserve staff are often recruited and trained and, depending upon the languages involved, interpreters may be needed.
2iv) Preparation - testing the processes
It’s important to have clear aims for tests. Some typical aims might be:
- to test the data collection procedures and enumerators' ability to follow instructions
- to test public knowledge of, and confidence in, the census authorities and the census process
- to test the processing of data
It takes considerable time to design a test, evaluate the results, make any necessary changes and possibly to re-test. Adequate time needs to be allowed for testing in the census project timetable.
3) Enumeration – gathering the census data
For most countries this is the most costly part of the whole operation. Once is has been decided how the population is to be enumerated, or counted and appropriate forms have been designed, the length of the data- collection period needs to be established.
Although the census will refer to a single night (census night), it will not be practicable to conduct the entire data collection exercise the very next day. This means there has to be a period of time set as the ‘collection period’. If this is too long, peoples' memories will become unreliable - if it is too short, excessive numbers of enumerators will be needed. A collection period of two to three weeks is unusually set, but this will vary according to local circumstances and available resources.
4) Processing the census data
How will the census data be captured into the census database? Popular options include manual data input and OMR or ICR scanning. Decisions will need to be made about how to verify data, handle errors and omissions. For example: what editing and data input techniques will be deployed.
5) Census data evaluation
Most developed countries carry out some form of census evaluation programme. This is often a coverage-check to estimate the extent of undercount. The quality of the data should also be checked for ‘response error’. Decisions will need to be made on what to do about the errors detected and if the census estimates be adjusted to take them into account.
6) Analysis of census data
This is an ongoing phase of a census project with data being analysed in many ways using various parts of the data, or datasets. One of the most common and immediate requirements is to determine the population size and population breakdown by region. Local government funding typically relies on this data for the allocation of their budgets.
7) Dissemination of census data
Finally, important decisions need to be made about the dissemination of data:
- what tables will be produced, and in what order (given that the end-to-end census process can take months or even years)?
- what strategies will be used to avoid inadvertent disclosure of individuals - this is especially important with small-area data?
- will subsets or micro-data be made available and, if so, in what form and under what conditions and safeguards?