POPULATION DATA

CHAPTER04:                                                                     

POPULATION DATA

Population data is the information pertaining to population in terms of economy, social and demographic matters.

Source of Population Data 

Source of population data are divided into two;

(i)                 Secondary source of data

(ii)               Primary source of data

Primary Source of Data

Also known as traditional source of data. Example of primary source of data area:

(a)    Population census

(b)   Demographic sample survey

(c)    Vital registration

Secondary Source of Data

Also known as non-traditional source of data. Examples of secondary source of data are:

(a)    School register

(b)   Labor register

(c)    Medical records

(d)   Baptismal records 

(e)    Religion/parish records

(f)    Maternal clinic and child welfare

(g)    Published reports, unpublished reports and statistical abstract.

Note: Secondary source of data are obtained from other findings (second hand data) while primary source of data are obtained from first hand data. Therefore; in developing countries, demographic data comes mainly from census, sample survey and vital registration.

I.  Sample Survey 

Sample survey is the system of collecting statistical information about population which involves a selection of a suitable represented size in the community to form population that provides information on death, birth and migration.

It is purpose is to represent information of the area concerned such as ward, district, and region within a particular territory. A sample survey can be into:

1.      Single round sample survey: involve only one interview with respondent

2.      Multi round sample survey: involves interviewing the same respondent several times.

Advantages of simple survey

1.      Is simple to conduct and administer

2.      It is more flexible than census as it allows a wide range of questions

3.      Is less expensive compound to census as it involves only a sample

4.      Allow more detailed information to be collected

Disadvantages of sample survey

1.      Suffer from sampling error due selection of sample to represent the majority

2.      Not easier to compare the data obtained from sample survey from other countries 

3.      It is poor in coverage, due to small population and areas considered

4.      Not accurate due to generalization of data from the population

II. Vital Registration 

Vital registration is the way of collecting population data through death registration, birth registration and marriage registration. In addition, this is the basic source of data of a population. Now day in Tanzania vital registration is done by RITA (Registration and

Insolvent Trusteeship Agency).

In the other way Vital or civil registration is the system by which a government records the vital events of its citizens and residents. Vital registration creates legal documents which may be used to establish and protect the civil rights of individuals, as well as providing a source of data which may be compiled to give vital statistics.

In contrast to censuses, which collect information on every member of a population at a single point in time, vital registration systems collect information on individuals as demographic events occur. You may also see ‘vital registration’ called ‘civil registration’, which is the preferred term of the UN Many vital registration systems record births, deaths, foetal deaths, marriages, divorces and adoptions, as well as recording information on the individual who experiences the event, such as age, religion, occupation etc. These data are then compiled into vital statistics bulletins

Reasons to why most of events are not recorded in Vital Registration(in African countries).

(i)     Passive in nature of registration system.

(ii)   Costs involved in records.

(iii) Birth and death occurring at home cannot be easily be registered/recorded.

(iv) High illiteracy rate.

(v)   Lack of skills to registration staff.

(vi) Most of people not seeing the advantage of these records.

     (vii) Most of are located in urban areas (district, region and cities) and not in villages.

Usefulness and advantage of Vital Registration: 

1. To check correct age of children for starting school
2. To know causes of accident and death
3. To provide health service needed to the population
4. People to have legal rights to the national.

Disadvantage of Vital Registration

(1)   It is very expensive since it needs permanent infrastructure and personnel.

(2)   Second hand information given by people may be seemed to be not are not concerned with events (of death, birth and marriage).

(3)   Poor coverage due to the lack of registration canters and registration officer.

(4)   No legal follow-up (No information of laws)

(5)   Registration sometimes are done by other officers who do it as an extra duty, like Nurses, hence information can be incomplete.

Advantages

Disadvantages

The continuous nature of data collection (or supply) for population registers means that the information available is current, whereas information from decennial censuses may be many years out of date. Population registers can be updated almost instantaneously, meaning that there is no long waiting period for the data to be collated and analyzed as there is with decennial censuses. There is a potential for linked records, meaning that (anonymised) individuals can be followed through the life course for research purposes.

The type of data available is determined by the nature of the administrative departments collecting it. On a census, additional questions can be easily added to give data on a specific area of interest. When first established, the quality across different departments or regions may be of uneven quality. Events occurring before the start of registration, or occurring while the individual was abroad, may be excluded. The fact that the record is permanent, follows you through life, and is linked between departments, may be unacceptable to some with concerns of a “Big Brother” style society. There are also concerns regarding the potential for data leaks.

Qn: Write down the merits and prone of vital registration.

The advantages of vital registration can be divided into two categories:

• Legal
• Statistical

Legal advantages to vital registration                                                                                        When a demographic event is registered, legal documents are issued as proof of this event. This confers a range of legal benefits upon the holder.

• Registration of a birth establishes and protects the identity of an individual, and confers citizenship upon them. This legal recognition entitles the individual to state services and protection from exploitation.
• The establishment of a legal identity (and the corresponding legal documents) allows individuals to vote, to be registered for education, and to move between countries (through the ability to apply for a passport).
• In many countries valid death certificates are required before a burial permit can be obtained.
• Valid death certificates are required before life assurance payments will be made.
• In the event of a death, marriage certificates and birth certificates showing parentage are important in securing inheritance and land rights.

Statistical advantages to vital registration                                                                                                     In addition to legal benefits for individuals, there are benefits for society which result from the availability of high quality, up to date information on births, deaths and causes of deaths.

• Continuous registration of births and deaths allows for intercensal population estimates.
•  Death registration and detailed cause of death classification are important for understanding the health of a population. This can then be used to formulate and prioritize effective public health policies and interventions.
• The same information allows for monitoring of the effectiveness of public health interventions. This allows governments to ensure that tax money is spent in effective ways, and gives accountability to aid donors that donated money is improving the health of a population in the way that it was intended.
• Vital registration also allows for monitoring progress towards targets, such as the Millennium Development Goals (MDGs). Without continuous registration of vital events, it is difficult to know whether progress is being made and whether the target is likely to be reached by 2015

Quality of Vital Registration Systems                                                                                                           The table below shows the qualities a vital registration system should have if it is to meet the needs of its users.

	Measure
Accurate	In order for a vital registration system to be accurate, it should have: High coverage (% of population covered) High completeness (% of events included) Low levels of missing data Low usage of ill-defined categories used as cause of death Low numbers of improbable classifications Consistency between cause of death and general mortality
Relevant	In order for a vital registration system to be relevant, it should give: Routine tabulations Small area statistics
Comparable	Vital registration systems should be: Comparable over time Comparable across space
Timely	For vital statistics to be useful in informing health policy, they must be: Produced regularly Have little time between collection, compilation and publication
Accessible	For vital statistics to be accessible, they should be: Produced in a number of different media formats Provide information about the data (i.e. collection method, definitions, manner of presentation, potential for error etc.) Provide a responsive user service to distribute data, clarify queries and engage with data providers

Adapted from Mahapatra et al. (2007)

 

On some levels, as suggested earlier, it makes sense to expand the number of questions asked of individuals and households – the marginal cost of adding an additional question is relatively small compared with the overall scale of the census project. However, it is not uncommon for a form of political horse-trading to occur whereby if one ministry or agency secures the right to field a question or questions in the census (e.g. on access to piped water), another ministry may argue that it should also be entitled to field questions (e.g. on access to mobile telephone). The result of such a process can result in long, cumbersome and unwieldy census instruments. In turn, this may compromise the overall quality of the data collected as respondents and enumerators may become disaffected with the length of the questionnaire. In addition, the extra questions will add to the complexity of the data set and any editing performed on the data, on the size of the data files that result, as well as increasing the time taken to process and collate the information.

In general, it is preferable to keep the number of questions asked in a census down to a minimum, focusing on those data required to enumerate the population and on variables that require large sample sizes to measure accurately. The results from the enumeration can be used as the sampling frame for specific and much more detailed enquiries that can be conducted on a sample basis on a much smaller portion of the population. Examples of such enquiries would be Demographic and Health Surveys;

What information should be collected in vital registration?                                                                                                                                  The United Nations (UN Department of Economic and Social Affairs, Statistics Division 2001) lists information which should be considered high priority when registering vital events. These are presented in the table below. The full UN report lists further characteristics of interest which are not considered high priority, as well as further information on the definition of each of the topics.

	Recommended High Priority Topics
Births	Date of occurrence of birth Date of registration Place of occurrence of birth Place of registration Type of birth (i.e. single, twin, multiple etc.) Attendant at birth Characteristics of the child Sex Birth weight Characteristics of the mother Age (or date of birth) Marital status Educational attainment Place of usual residence Children born alive to the mother during her entire lifetime Children born alive to the mother and still living Foetal deaths to the mother during her entire lifetime Date of previous live birth Date of marriage Characteristics of the father Age (or date of birth) Marital status Educational attainment Place of usual residence
Deaths	Date of occurrence Date of registration Place of occurrence Place of registration Cause of death Certifier Age (or date of birth) Sex Marital status Place of usual residence Place of usual residence of the mother (for deaths under one year of age)

This diagram shows the levels at which information from vital registration is collected and compiled. As you can see, the levels of data reporting and compilation move from a local (individuals and towns etc) to a national scale (Registrar General and National Statistics Office).

Adapted from Setel et al. (2007)

 

A note on registering cause of death                                                                                                    Registration of cause of death, as certified by a medical practitioner, has the clear benefit of providing a health profile of a population. This allows priorities to be set in public health, and for policies to be formulated. If accompanied by information on characteristics of the decedent, such as age, sex, occupation, ethnicity etc., it is possible to identify mortality differentials between groups.

The cause of death which is used for statistical purposes should be the underlying cause of death, i.e. the disease or incident which initiated the chain of events leading to the death. This should be coded according to the rules and guidelines outlined in the latest revision of the International Statistical Classification of Diseases and Health Related Problems (ICD). Coding according to these rules allows for valid international comparisons.

One of the criteria for a vital registration system to be considered high quality is that the data it produces must be “timely”. This usually refers to the efficiency of the departments in charge of collecting, collating and publishing the statistics and their ability to produce reports regularly and within a useful timeframe.

However it is worth noting that the timeliness of the data produced is also reliant on individuals reporting events soon after they have occurred. In many countries it is a legal requirement for the event to be reported within a set timeframe. For example, in the UK all births must be reported within 42 day. However, in many developing countries vital events might be notified to authorities many years after the event has occurred. Of the births occurring in South Africa in 1998, only 58% of the births registered within five years were registered during the year of birth or the following year.

                     

III. Population Census 

Census is the official counting of a country’s population. OR is the process of counting, collecting, compiling demographic, economic and social data to the specific time to all people in the country.

United Nation’s definition of a census:
"The total process of collecting, compiling, analysing, and publishing or otherwise disseminating demographic, economic and social data pertaining to all persons in a country or in a well-delineated part of a country at a specified time."

There are several aspects of this definition that are worth emphasizing.

1. This definition refers to the “total process”. It not sufficient to simply collect and collate information in a census. The data collected must also be analysed, published and disseminated.
2. The scope of a census encompasses demographic, economic and social data. Thus a census will often seek to collect more than just a simple headcount of the population. The reasons for this relates to the logistics of the exercise: if one is going to try to individually enumerate each person in a population, the marginal cost of collecting additional information (on income, education, housing etc.) is low, although will lead to an increase in the length of (and hence time taken to complete) the census instrument. The implications of this are discussed in a later section. Often the census is referred to as a Population and Housing Census to emphasise the broader ambitions of the census.
3. The census aims for universality, that is, to enumerate all people in a population. This is less simple than it may seem. The problems associated with attempting to define and count “all the people within a population” will be discussed in the following pages.
4. The census aims for simultaneity - it seeks to produce a snapshot of the population at a point in time. With the exception of very small and compact populations, it is usually impossible to actually enumerate a population on a single date. In many countries, census enumeration takes place over a number of weeks. To this end, censuses usually have a defined ‘census date’ for which responses are elicited, regardless of when the questions are actually put to the respondent. Households are asked to recall the people who slept in the house or who were usual members of the household on the census date. Births and deaths that occurred between the census date and the date of enumeration (when the household was actually counted) should be omitted.

Back ground of census                                                                                                                               Censuses have been used for thousands of years. Initially, their prime purpose was for levying taxes or raising armies. Egypt, 5000 years ago, sought to produce a list of households and household members every second year. Imperial Rome, around the beginning of the Christian era, sought to count the population every five years, largely for taxation. The modern census, however, evolved in Europe in the 1600s as an aspect of 'political arithmetic' whereby countries sought to quantify the military and fiscal power of the state. Sweden’s first complete census occurred in 1749, with other European countries following soon in the next hundred years. The first census in the United States occurred in 1790, and the constitution mandates a census to be held every ten years; the results are fundamental to the allocation of seats in the (lower) House of Representatives.

Characteristics /Feature of Census

(1)   Universality

      Involves all people in the nation

      Involves a specific territory (coverage)

(2)   Simultaneity.

      Defined for different time

      Take place in a specific time interval of period

(3)   Confidentiality.

      Secret data for each individual should be kept

(4)   Sponsored by government

      Is involved by Government sponsorship to be conducted.

(5)   Costful of time and money

(6)   Individuality.

      Individual is primary enumerated and recorded his/her data.

(7)   Defined periodicity.

      Involve specific time interval especially 5 or 10 years of time interval

(8)   Regularity.

      Regular definite interval

Methods of Enumeration of Census     

(i) Canvasser/enumerator method: refers to the official and enumerate each house and collect data for each individual.

(ii) House hold method: Here questionnaires are sent in the house hold in advance of the house to find out the data

Method of Census Taking

(1)   Defecto: A person is counted where he/she found in the night.

(2)   De jure: Person is counted based on the permanent residence. 

Types of Census 

Types of census can be categorized according to approach under taking censuses or according to the time interval.

1. According To the Approach, Census can be:

      (i)  De jure census: Is the one which people are counted according to their usual place of residence. Only permanent members of household are counted. This method is disadvantaged by regarding people as they are static while they are dynamic.

      (ii) De fecto: Is the one in which people are counted wherever they are found on the day of enumeration. All people who stayed in the household for the night are counted.

2. According To the Time Interval, census can be: 

(i)  Quiquenial census: Refers to the census that carried out after every five years.

      (ii) Decennial census: Is the type of census carried after every ten years.

Advantages of de facto

1.      It is clear and simple because involves only those physically present in the census night are to be counted

2.      Avoid the distinction between temporary and permanent residence

3.      It is suitable for developing countries where majority are illiterate  because can be interviewed by census enumerators

4.        It is time saving since the time used to enumerate is short in obtaining the information

5.      Not easier for manipulation, as everyone is counted according where he/she

Advantages of de facto

1.      People like pilots, sailors and in transits may miss enumeration when they will be on work during night before census

2.      It is very costful in term of financial and human resources

3.      It may give wrong impression of population size for areas with high migration and seasonal mobility

4.      Enumeration is fast hence may occur unnoticed mistakes

Advantages of de jure

1.      Is technically free from the time limit or seasonal mobility or migration

2.      May be suitable for people flying, floating or in transits  because can easily enumerated based on usual and legal residence

3.      Due to abundance time, lot of question can be asked so as to get accurate information

 Disadvantages of de jure

1.      It require real definition of permanent residence

2.      People with temporary residence cannot be accounted

3.      May not reflect the size of the population in the country

4.      Difficult to count people with permanent address

5.      There is always some uncertainty about what should be considered to persons’ usual residence

Contrast between de facto and de jure enumerations

An important distinction is often drawn between populations that are enumerated on a de facto (Latin, for ‘in actual fact’) and a de jure (Latin for ‘in law’) basis.

• De facto – The population is enumerated where it is found, regardless of the respondent’s usual place of residence.
• De jure – The respondent is enumerated at their usual place of residence, regardless of where they stayed on the census date.

Objectives/Purposes of Census

(a)    To provide complete account of all members of the country by age and sex.

(b)   To obtained the detailed statistics on the size, nature and distribution of labor force.

(c)    To determine the literacy and illiteracy rate of the population in the relevant age group.

(d)   To provide and get social and economic information on the house hold and the county in general.

(e)    To provide the general picture of the all places of the villages in the country and persons. 

(f)    To determine the total number of the population in the country hence to plan for the social service provision.

Advantages of census

The coverage aims to be universal The census provides an important sampling frame for subsequent surveys and studies The census can serve as a useful tool for ‘nation-building’, by involving the entire population Census data avoids the sampling errors that can occur with sample data Censuses provide data for small areas, such as districts and counties, which is vital for the planning of services

Disadvantages of census

The size and complexity of the exercise means that the content and quality control efforts may be limited The cost of carrying out a census means that most countries can pursue an enumeration only every ten years There is usually a significant delay between when the data are collected and the results released. Typically this delay is between 18 months to two years, and means that the census only offers a snapshot of the population at some point in the past Censuses are easily politicized – either by groups who feel that they might be systematically undercounted by the exercise, or by parties with a vested interest in seeking to ensure that their group’s population is found to be larger than that of other groups

Importance of Population Census

The fundamental purpose of the census at a glance:

• Provide the facts essential to government for policy-making, planning and administration. 

• Decision-making that facilitates the development of socio-economic policies -enhance the welfare of the population. 

• Provides important data for the analysis and appraisal of the changing patterns of rural/urban movement and concentration, the development of urbanized areas, geographical distribution of the population according to such variables as occupation and education, as well as the socio-economic characteristics of the population and the labor force. 

• Aids in the decision-making processes of the private sector. Population size and characteristics influence the location of businesses and services that satisfy the needs of the target population.

How do we Use the Census Data •Development planning purposes •Estimation of levels and variations in population and housing characteristics •Estimating sources of labor force •Identifying the role of women and their economic and social standing •Learning about special population groups •Use for research purposes •Use for economic purposes. National development requires a well organized statistical system allowing planners to work on the broad set of statistical indicators that are indispensable for the development and improvement of planning. In order to involve the statistical system in the planning and delivery of the designed and desired statistical data Who can make use of the census information? Everyone inside the country or outside it can use the census data; accordingly, they serve for a great     variety of uses. A great deal of information is available on the CBS website and on the sites of international organizations. Additional information can be acquired by a direct application to the CBS.

The information provided by the residents is kept strictly confidential

The data collected appears only as statistical summaries, and it is not possible to identify the person or business whose details were recorded in the questionnaire. The Central Bureau of Statistics is prevented by law from transmitting to any other party - governmental, public, commercial or private - information that will make it possible to identify the source. The law is binding on all the Central Bureau of Statistics employees. The following are examples of possible users and uses: A.     Government ministries - the census data are available to decision-makers as a basis for setting policies in various fields: education, health, and welfare, dealing with various levels in the population, housing and development, transportation and other services. Examples:    Planning and provision of services in the educational system according to the needs of the      population and the age of the children.    Planning of public transportation and transportation infrastructure, according to the projected      amount of traffic in the area.    Planning a system of assistance to the needy.    Development of infrastructure according to the needs of the population.    Channeling of budgets to local authorities.  B.     Local authorities - the census data are available to decision-makers in local authorities as a basis for setting local policies in each locality, according to the needs of its population. The data assist in learning about the characteristics of neighborhoods and populations in the localities. Examples:    Examining the need for establishing early childhood services and public gardens in areas      where there is a high percentage of children of this age.    Using the data in determining municipal tax areas adapted to the characteristics of the      population. C.     Bodies of research - conducting research based on census data. Population censuses are an important resource for research on trends in the composition of a population and its distribution, as well as a source of analysis and assessment of the changes occurring in the population, and construction of a forecast regarding the directions of its development. Examples of research:   Means of transportation to work and socio-economic status in Israel.   Migration from development towns (from the periphery to the center or from one locality in the     periphery to another).   Changes in education and fertility patterns of Moslem women in Israel.  D.     Private and public companies - conducting research for purposes of acquiring commercial information to serve as a basis for market research, assessment of the demand for products and services, and assessment of the supply of personnel. Examples:    Identifying concentrations of old structures, by companies dealing in structure restoration.    Allocation of the maximum support by the State Lottery to various localities; which is     determined, among other things, based on indices developed from census data.  E.     Journalists - acquisition of information from the census data, on subjects which serve for conducting research and as backgrounds for articles. Examples:    Acquisition of information on socio-economic characteristics of localities, for an article on the     state of education in them.   Acquisition of information on the average wage in various localities and comparing it with the level     of development in them.  F.      Students and pupils - writing seminar papers and research projects for graduate degrees, based on data from the population and housing census; writing papers for school. Examples:   Use of data on areas in which there is a high concentration of families blessed with many     children, for research projects in sociology.  G.      The general public - use of data in a wide variety of many fields, relevant to each individual Examples:   Use of information on a residential area, in order to decide on a change of residence.   Acquiring information on the subject of employment and wages by occupation, which may     direct youngsters in their decision to choose a field of study.   Identification of locations suitable for opening a business, by the self-employed.

• Population censuses also constitute the principal source of records for use as a sampling frame for the household surveys during the years between censuses.

Limitation of Census

a)      Low literacy level among the people, limit the process of under taking census

b)      Poor coordination in the process of under taking census between the people and enumerators.

c)      Poor coordination in the process of under taking census between the enumerators and the respondents (poor communication).

d)      Poor framing of questions creates fear among the individuals.

e)      Political instability of a place/country.

f)       Transport problem to the remoteness area also limit the process of under taking census.

g)      Problem of misreporting the information e.g. Age and population characteristics 

h)      Shortage of useful material and facilities.

i)        Poor payment to the enumerators

j)        Omissions of some members especially for those found absent hence poor coverage. 

k)      The expenses in conducting census through training manpower, wages, and buying facilities/materials.

Summary                                                                                                                                  Population data can be gathered from a number of sources. This session has outlined the primary sources, their advantages and disadvantages, and outlined some options for when data from these sources are not available.

Censuses are the main source of data on population stock. Ideally held every ten years, they involve an enumeration of the entire population of a nation and often include the collection of additional information on social and economic characteristics. However, censuses can only provide a “snapshot” of a moment in time, and by the time all the data has been collated, analyzed and disseminated, it will often be a number of years out of data. Furthermore, censuses are expensive, time-consuming and require large amounts of man-power. Because of these disadvantages, a number of countries have moved towards population registers. These collate and link information from vital registration and administrative registers, and provide an up-to-date and near instantaneous profile of the population.

Vital registration – the registering of vital events, such as births, deaths and marriages – remains the ideal source of information on demographic events. However, many countries in the world do not have a high quality system for vital registration, if they have a system at all. In these situations it may be possible to use alternative methods to estimate the number of demographic events, such as sample registration, demographic surveillance sites and verbal autopsy. Nevertheless, these should be seen as interim measures, with a comprehensive system of vital registration still seen as the ultimate goal.