Lesson 4: Use of Census and Related Population Information
- Identify sources of population information for planning
- Evaluate the quality of information, and
- Explore ways to use population and related information
Acquire skills used to obtain, evaluate and use census information as well as other types of population information used in program planning and management.
This session presents the types of information that can be obtained from the census of population and housing. It is also designed to assist planners in evaluating the quality of census information. Techniques and strategies to collect population information from other sources including representative sample surveys and vital statistics reports will also be covered.
In most countries, the census is conducted every 10 years at a minimum. For the period between census takings, information collected from representative sample surveys can be used to provide population information. Household surveys on agricultural production, manpower, health, housing, and transportation usually collect information on the characteristics of the population. These data can be used for planning purposes.
The lesson ends with a discussion of where to obtain information on vital statistics including births, deaths, fetal deaths, marriages and divorces.
4.1 What is a Census?
The United Nations defines a population census as the total process of collecting, compiling, and publishing demographic, economic, and social data pertaining to a specific time to all persons in a country or delimited part of a country. As part of a census count, most countries also include a census of housing. It is the process of collecting, compiling and publishing information on buildings, living quarters and building-related facilities such as sewage systems, bathrooms, and electricity, to name a few.
The United Nations lists four essential features of a census:
- Each individual is enumerated separately; the characteristics of each person within the household are recorded separately.
- The census covers a precisely defined territory and includes every person present or residing within its scope. The housing census should include every type of building and living quarters.
- Each person and each type of building and living quarters is enumerated with respect to a well defined point of time.
- The census is taken at regular defined intervals, usually every 10 years.
4.2 Types of Census Information
Most censuses collect information on:
- Individual residents aged 0 to 100+
- Households including families and unrelated adults
- Housing and related facilities.
A census of population collects information on basic population characteristics including age, sex, marital status, household composition, family characteristics, and household size. Information is also collected on economic measures including labor force participation, occupation, place of work, employment-related industry, and educational attributes such as school attendance, educational attainment, and literacy. Geographic and migration information is also collected. Questions on place of birth, place of usual residence, duration of residence, and prior place of residence allow planners to examine population movements. Some countries also collect information on births and deaths, especially those that do not have a system that adequately registers these vital events.
A census of housing collects information on buildings, living quarters and related facilities. Information is collected on buildings that are used for residential, commercial, or industrial purposes, including the type of structure, the construction materials used for the outer walls, and the year of construction. The type of information that is usually collected on living quarters includes the type and location (rural or urban locale) of the quarters, the number of rooms, the occupancy status and number of occupants, and the types of available facilities such as water, toilets, sewerage, bathing, cooking areas, and lighting. Living quarters can be housing units or collective living quarters. Data on living quarters provide insights into the type and quality of housing that exist in rural and urban areas throughout the country.
4.3 Using Census Information in Planning
In a number of countries, the population census plays a major role in the allocation of elected political seats in government. The number of elected officials for each governmental administrative unit is determined by the population size of a given locale. For some countries, the information is also used in the allocation of government resources. The size of the population determines, in part, the amount of money that is provided by government for development efforts.
For planners, census information is used in just about all planning decisions. The census of population provides information on the age and sex distribution, in addition to household composition and size, all of which are vital in determining the needs of different segments of the population. The census of housing allows planners to assess changes in the quality of housing and related facilities and plan for future housing needs. Table 4-1 provides possible planning-related uses for population and housing data.
4.4 Evaluating the Quality of Census Data
The quality of census information improves each time it is taken. Errors, however, can be found in both developed and developing country census data. Errors in the census can be due to shortcomings in data collection, including failure to count all people. In most countries, there is a small percentage of the population that is homeless and live in the streets because they are too poor to afford shelter. The homeless segment of the population tend to be the hardest people to record during census counts in both developed and developing countries.
Another data quality problem is the failure of respondents to provide correct information. In countries that do not have adequate vital registration systems to record births, residents may not know their exact age and/or the ages of members of the household. The census office checks the quality of age information and adjusts the distribution to account for age misreporting.
In some countries, two types of census forms are used; one that includes all of the residents, and one that includes a sample of residents. When countries wish to obtain detailed information about households, they select part of the population and use a longer questionnaire. The selection of respondents is based on sampling procedures to ensure that a representative population is selected. One of the problems with sample data is that sampling errors can occur by chance.
Errors can also take place when census data are compiled and entered into computers. Human errors can emerge during stages of data processing, analysis and compilation.
Governments are aware of potential errors in census data and are continuously evaluating the quality of information. Most statistical offices conduct a post enumeration survey to check on the quality of information. Prior to the census, they identify strategies to reach those whom are homeless. Governments also search for ways to control human error in data processing.
Given the possible problems with census data, planners need to evaluate the quality of data obtained. Suggestions on ways to check the quality of census information are listed below.
- Population growth or decline may be due to changes in census boundary maps, and not changes in population. Close evaluation of changes in census boundary maps is necessary when analyzing population growth or decline between census periods.
- Compare the results to prior census results with old population projections for the area. Determine why change has occurred.
- Building on suggestion 2, develop population pyramids for the prior and current census. Look for changes between age groups. For example, children aged 10-14 in 2000 were age 0-4 in 1990. If change exists in doing this comparison, try to determine why. As an added check, examine the results for ages 0-14 with school enrollments to see if increases or decreases have taken place.
- Examine the procedures for data collection. Were the homeless counted accurately?
- Speak to others in agencies and organizations involved with collecting population and related information. Are their collective results supportive of the census report?
4.5 Other Sources of Information and Data
Representative Sample Surveys
National, regional or state/province representative sample surveys that collect population information on individuals and/or households are a source of data that can be used by planners between census takings. Government ministries, statistics offices, and universities are all excellent resources to learn of available surveys.
It should be mentioned that representative surveys do not have to focus exclusively on population topics to provide useful information for planning. For example, agriculture, manpower, and housing studies, will include population information as part of the background characteristics on households. These surveys usually have information on the age and sex of households, educational attainment, labor force participation, and structure of the household including household size, to name a few. Look at surveys that you have used in the past and determine if they provide population information that can be used to guide planning decisions.
Caution: These surveys are useful if they represent the true or actual population. You can evaluate whether or not it is a representative sample by investigating the sample selection process. If everyone or every household had an equal chance of selection, then its possible that it is a representative sample survey.
A national representative sample survey that is available for many developing countries is the Demographic and Health Survey (DHS). The survey is designed to provide governments with information on fertility trends, maternal and child health, family planning use, and knowledge of AIDS and sexually transmitted diseases. The DHS includes several key fertility rates including the age specific fertility rate, the general fertility rate, and the total fertility rate. It also provides information on infant and child mortality rates. The reports are primarily used by Ministries of Health at the national and regional levels for family planning, AIDS prevention programs, and the maternal and child health care services.
How can planners use the Demographic and Health Surveys?
The survey serves two useful purposes. First, the information on fertility behavior helps planners study trends in fertility. As mentioned in Lesson 3, high levels of fertility can lead to high numbers of children in the 0-14 age cohorts. The high proportion of youth will continue into the next decade since future mothers have already been born.
Second, the survey provides regional information on basic demographic characteristics of households between census takings. The published reports provide regional information on household size, sex of household head, levels of educational attainment, school attendance, and access to mass media. Information on the role and status of women including labor force participation, form of earnings, and occupation is also included. Planners may observe the age and sex distributions of regions to plan for different segments of the population.
Changes in housing quality, especially in countries where several surveys have been administered, may also be evaluated. The survey collects information on the availability of electricity, source of drinking water, available sanitation facilities, materials used for building construction, persons per sleeping room, and mean persons per room.
National statistics offices in most countries administer the Demographic and Health Survey. Survey reports and data sets are available for Sub-Saharan African countries, Asian countries, Latin American and Caribbean countries, and European/Eurasia countries. In some countries two to four rounds of the survey have been administered over the past 15 years. It is possible to analyze several surveys for a given country to observe changes over time.
Acquiring DHS Information and Data
The published reports are available at low costs through most central statistics offices and/or the Ministry of Health. The reports can also be ordered through the web site of the Demographic and Health Surveys. Survey data sets can also be downloaded free at the DHS web site along with instructions on how to place the data set on your local computer.
Vital Registration or Civil Registration System
Mortality statistics are used in population projections to calculate the probability of surviving into a future period of time. Information on the cause of death is also used to develop and implement plans that protect the health of communities. Planners are concerned about environmental factors that affect the health of residents including the quality of water, sewage systems, living quarters, roads, public transportation, and work environments. Information on births and deaths can be obtained from vital registration systems, sample surveys, church records, and health records.
- A vital registration or civil registration system is designed to record vital events such as births, deaths, fetal deaths, marriages and divorces that occur among a population. Most countries have legal provisions within their constitutions to ensure that vital events are recorded. Government legislation defines the type of vital events that must be registered, the time requirements for registration, the designated person or office who is responsible for registration and the place where the registration is to be made. The establishment of civil registration systems varies from continent to continent.
Who collects information on vital events at the national and sub-national levels?
Studies conducted by the United Nations in 1985 and 1994 provide information on who collects and compiles vital statistics information in developed and developing countries. In most countries, a central statistics office is responsible for the national compilation of vital statistics. The location of national statistics offices varies among countries. In a study conducted in 1994 by the United Nations, it was observed that approximately:
- 29 percent of the statistics offices were located in the Ministry of Finance and Economics
- 26 percent reside within the Ministry of Planning
- 16 percent are in the Ministry of Health
- 11 percent are in the Ministry of the Interior.
The second type of office that compiles vital statistics information is a national civil registration office. Many of these offices are located within Ministries of Finance, Economics, or Planning. Other ministries where central statistics offices and national civil registration offices can be found include the Ministry of Local Government, the Ministry of Home Affairs, and the Office of the President. In some countries several units of government jointly compile vital statistics such as the Ministries of Health and Planning.
Before relying on one particular data source, investigate the ability of the agency to collect accurate and thorough information at the national and sub-national levels including districts and counties. Completeness of registration is fairly high in South American countries including Argentina, Chile, and Colombia where coverage is 90 to 100 percent. A fair number of Asian countries have comprehensive registration systems with 90 to 100 percent coverage including China, Sri Lanka, South Korea and Japan, to name a few. Most European and North American countries also have 90 to 100 percent of vital events registered. Vital registration systems in most Sub-Saharan African countries do not adequately or completely collect information on vital events.
Access to vital statistics at the regional, district, or county level vary by country. In North American countries including the Caribbean, information can be obtained through district or county civil registration offices, court offices, and municipal offices. In South American countries, local vital statistics can be obtained from health centers, civil registration offices and from district registrars. In Asian countries, information can be obtained from municipal offices, birth and death registration offices, local government offices, health centers including the chief medical office, and civil registration offices.
In Sub-Saharan African countries, vital statistics can be obtained from district civil registration offices, the district commissioner's office, health facilities, district courts and in some cases through district representatives. A major problem is that all births and deaths are not reported to a government facility, especially infant deaths. Planners in African countries will need to seek information from a number of sources to determine the number of births and deaths that occur within their planning locale. Additional places to seek information include the Ministry of Health at the state, district, or county level, health care providers within the traditional health care system including traditional birth attendants and herbalists, religious institutions, private health clinics and non-government organizations that provide health care services.
Sample surveys and studies that are conducted by government offices and universities can be used to evaluate the quality of vital statistics. The Ministry of Health or national health department, as well as universities conduct a range of studies on health care status and causes of deaths. The state or province Ministry of Health or health department may be a source of information for government reports. University libraries may be a source for journal articles and books on health care in the country.
Indirect Population Information
Departments or Ministries of Health and Education also collect statistics that indirectly provide information on population growth or decline. State offices and district offices that provide primary and secondary education services collect information on the current number of children enrolled in school. In countries with high levels of fertility, a high proportion of the population under the age of 15, and high rate of school participation, school enrollment statistics for several points in time can be used to determine if population growth is occurring among children ages 0-14. Information on childhood immunizations can also be used to determine growth trends, especially in areas where a high percent of children receive immunizations. Other sources of information that parallel population growth may include new housing construction or the growth of new squatter communities.
4.6 Summary and Exercise
Population information is needed to guide all planning decisions. Lesson 4 provided sources of available census-related information and various options to evaluate the quality of information obtained. In addition, strategies for using population- related information to develop, revise, implement and evaluate sub-national plans were introduced.
- Think about how you have used population information in the past. What type of information did you obtain? Where did you obtain the information? How did you evaluate its quality?
- Identify additional sources of information. What type of information do you need? How will you use it? Where will you find it? How will you evaluate the quality?