The concept of Population Survey

Population survey is a prominent aspect in the field of counting through which actual strength and number of manpower can be measured scientifically. There is no denying the fact that in Bangladesh such survey has been carried out in many times but the criteria that have been used as performance indicators which have not satisfied the targeted goals. After survey it is seen that many complaints have been received from different regions where double counting, triple counting and even forged people being fictitious have been explored. The word survey originates from census which emanates from the Latin term censure, envisaging ‘assess’ and it by and large indicates the official complete counting of a country’s population. Besides population survey, there are two other types of surveys that are frequently conducted. These are agricultural survey or counting of agricultural holdings and economic survey or counting of economic units. All the three types of surveys-population, agricultural and economic- are on a regular basis held in Bangladesh. However, as the population survey illustrates the numerical universe of the country, all other surveys depend on population survey as a concrete framework of data collection.

Considering total counts of population, household or land sporadically in villages was ingredient of social life from early times in the Indian subcontinent as well as the areas now comprising Bangladesh. The system sustained in the Mughal period predominantly throughout their reigns but chopped in disuse after the decline of the Mughal Empire. The first population survey for the whole country on modern line following the one designed for the Belgian Survey of 1845, was established by the British Government all the way through India counting the present day Bangladesh territory in 1881as a decennial procedure. The 1881 populace survey was paved the way by a number of surveys of investigational nature taken during 1769-1855 by the East India Company and by the Crown during 1858-1869. However, as compared to up-to-the-minute surveys, these surveys were disconnected, barely methodical and lacked standardization. The methodical challenge to determine the entirety population of the complete countryside by actually counting heads was made between 1867 and 1872.

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Feedback form is the heart of survey taking and reflects the basic purpose for which the survey is taken. Since 1981 survey, Bangladesh population survey have included two questionnaires- the short or the main questionnaire that is universally canvassed and the long questionnaire that is used in the sample survey. The sample survey is conducted after the main count to collect detailed and supplementary information on the basis of sampling a portion of the counted population. Since 1981 survey the OPTICAL MARK READER questionnaire in completely pre-coded form has been successfully used in the total count to collect the population and housing information with considerable ease in field record, reduction in data capture time and complete elimination of human error in data capture process. Specimen of the OPTICAL MARK READER forms used in the main counts of 1981 and 1991 survey are provided as appendices. Since the 2001 sample survey is planned to cover a fairly large segment of the population [nearly 20%], to reduce data capture time and error free data entry, the sample survey questionnaire will also be in OPTICAL MARK READER format.

The topics included in the main survey questionnaire are of two types -information collected for each individual person and housing information. To fulfill the requirements of a simple, short and OPTICAL MARK READER based questionnaire, only the key topics are included after a balanced consideration of several key factors. These include the priority national needs, willingness and ability of the public to provide the information adequately, international comparability of the information both within the SAARC region and on a worldwide basis and human and financial resources available for conducting the survey to collect the information. Formulation and finalization of the survey questionnaire takes up greater part of the survey planning time, and extends usually over two to three years. For ensuring comparability of successive survey core topics are retained from survey to survey and addition or deletion of other topics is done sparingly. The questionnaire is finalized on the basis of several pretests in actual field conditions and on the scrutiny and advice of the survey technical committee that consists of academic experts, representatives of survey data users and business community, legislative body of the ministries, local governments and NGOs. whole topics enclosed in the survey include in addition to the core topics of the short questionnaire, the topics in the sample survey questionnaire, which are usually more detailed aimed at collecting flow type data compared to the bench mark type data targeted by the main survey. By way of supplementing the core topics of the short questionnaire, the sample survey questionnaire of the recent Bangladesh population survey have included topics of demographic, economic and social importance on both the individual and housing modules. On the individual module the following topics are included:

·         Fertility

·         Mortality

·         Migration

·         Physical disability and impairment

·         Causes of disability

·         Income of the household head and main sources of income

·         Status and the Institutional sector of employment

·         Place of work

On the housing and household module the topics included in the sample survey had been the following:

·         Rooms and floor space

·         Water supply system

·         Toilet and sewerage facilities

·         Cooking facilities

·         Lighting and type of fuel and electricity

·         Rental and housing costs of owner occupant housing

 

The population survey is undoubtedly the single most extensive, complicated and expensive statistical operation consisting of a complex series of interrelated steps, that the country undertakes. A key feature of the recent Bangladesh population survey is preparation and implementation of a comprehensive survey plan that fully reflects the strategic objectives of the survey and identifies the diverse survey operations to insure that they occur in their proper sequence and in a timely manner. Bangladesh survey plan divides survey activities into the following six phases:

·         Preparatory work

·         Record

·         Evaluation of record quality

·         Data processing

·         Dissemination of the results

·         Analysis of the results

Operationally, the six phases are not chronologically entirely separate or mutually exclusive but overlapping and interactive. The preparatory phase consists of several diverse activities and is the most difficult and time consuming usually taking around 60% of the total survey plan time. On the other hand it is the right conceptualization through satisfactory implementation of the key activities of the preparatory phase that makes or unmakes the survey.

Preparatory phase include:

·         Planning the survey calendar or the survey time Figure,

·         Fixation of the size of record area [EA]

·         Mapping work for dividing the whole country into EAs with the help of survey cartography,

·         Preparation of the survey questionnaire and its printing,

·         Plan of survey record including recruitment and training of field enumerators and supervisors.

The other activities are no less important. These include insuring proper legal basis for the survey, developing survey budget and system of cost control, development of survey administration, plan for PEQC and quality control, plan for survey publicity, data processing plan and plan for survey publication and dissemination of survey data and information. The survey calendar or time Figure indicates the sequence and estimated duration of each component operations of the survey. The key date in the calendar is of course the starting and closing dates of the general record of the population on which hinge all other operations.  Survey calendar in Bangladesh is usually drawn in the form of a bar or the Programme Evaluation Review Technique (PERT) chart, with separate bars of each main operation.

Survey budget provides careful financial estimates of the cost of each operation of the survey and is based on costs of the components and estimate of the total cost of the entire survey operation. And the budget together with the budget calendar is used as an instrument of effective control of survey operations. Levels of expenditures in the previous survey classified by survey phases form the basis of preliminary estimates that are modified to take into account general inflation and changes in the scope. One special feature of Bangladesh survey budget is foreign donor assistance that funds substantial portion of the total cost particularly foreign exchange costs of data processing and data input mercenaries and printing of OPTICAL MARK READER questionnaires.

        In a nutshell, mean cost per person itemized was around Taka 2 in 1981 in nominal prices that include costs of record, equipment, data processing and dissemination and all other costs, which increased to Taka 3 in 1991. The likely average cost in 2001 survey is projected at Taka 4. Survey EA: Success of the survey field record depends on fixation of the optimum size of record area and segmenting the country into record areas. For the purpose of counting, the target population is divided into four groups-population in dwelling houses, population in institutional houses [such as hotels, hostels, mess, jails, hospitals etc], and floating population [i.e. rootless or population without any permanent address] and population on transit [on the survey night]. Of these the largest group in the country is population in dwelling which accounts for about 98% of the enumerated population and the remaining groups around 2%. Since record of the population in dwelling as well as housing is done on household basis the size of EA is determined on the number of households an enumerator can cover within the stipulated period of field record, which in the 1981 and 1991 survey has been 3 days. The size of record varies between 90 to 110 households averaging around 100. Division of the country into record areas is done meticulously for urban and rural areas separately with the help of up to data base maps.

Population survey extends the concept of urban areas from survey to survey. Currently urban areas in Bangladesh include all the four statistical metropolitan areas [defined as the area including the per urban areas adjacent to the metropolitan areas], all municipalities and other urban areas that include growth centers and thana head quarters and the survey concept of urban areas is used universally.  

Each EA is provided with a geocode [a 7-digit hierarchical code that covers all the major and minor civil divisions of the country] and a separate map with a clear delineated boundary identified through prominent landmarks on the ground is prepared for each EA. Preparation of EA maps is done through country wide field operation which is done by counting all dwelling houses and their inhabitants, identifying EA boundaries on the base maps and is a major operation that takes greater part of survey planning. The finalized EA maps are reproduced and each enumerator is provided with a copy to insure accurate field record and avoidance of duplication or overlap in counting between neighboring EAs. Five EAs are grouped to form SAs or supervision areas and each supervisor is provided with a copy of the SA map. Totaling EAs and SAs the number of enumerators and supervisors is arrived at. Selection of enumerators and supervisors for the purpose of survey is done through another country - wide operation called zonal operation, which is carried out by the field net work of BBS.

The plan of operation is then prepared. The plan sets forth the countrywide survey publicity arrangements and other operational components of the survey plan. Survey publicity uses every avenue of nation-wide publicity particularly media, loud speaker, drum beating, and other traditional means. Other operational components include scheduling of field training of EAs and SAs delivered through a hierarchy of master trainers, and  the logistical arrangements for survey materials including dispatch of books containing survey questionnaire and return of the filled in questionnaires and record schedule. Specifying dates for training including mock record by all enumerators and supervisors and the dates for actual record around the specified survey night are the other key elements of the plan of operation.

The testing of the various aspects of the operation plan including record is carried out a few months prior to holding the actual survey in all EAs comprising a Thana in an operation known as Pilot Survey. The Pilot survey tests the operations planned for all stages of survey including record, processing and evaluation of results and provide information on the adequacy of field organization, quality control measures and training program and help identify the procedural weaknesses so that they can be rectified on time.  By using OPTICAL MARK READER schedule for survey record has simplified and cut down by at least two thirds the data capture time, while insuring an almost error free data capture process. This in turn has reduced substantially the overall data processing and tabulation time. In fact full tabulation of the survey is completed within one year of survey record which usually took around five to six years in pre- OPTICAL MARK READER survey. Use of OCR and other state-of –the –art data capture equipment are likely to reduce further the data processing time in future survey.

 Survey results are tabulated hierarchically up from mauza [and villages comprising mauza and mahalla and ward for urban areas], union, Thana, zilla, division and finally aggregated for the country as a whole. For the purpose of dissemination survey publication includes several volumes including the National Analytical Report and District Reports for each district of the country. These are supplemented by special reports on Post record quality check survey, Sample survey, Analytical report on urban areas and an administrative report on the survey operations. In addition to hard copies, all survey data are available in machine-readable forms-in diskettes and CDs.

Survey Evaluation: Post Record Quality Check: A unique feature of Bangladesh survey is post record quality check survey that is conducted immediately [usually 15 days to a month] after the main count. The purpose is to check the overall quality of the survey main count by estimating the degree of coverage error i.e. omission or duplication of persons and content error or the errors in responding to survey questionnaire. Typically coverage error in Bangladesh survey relate to missing of persons and entire households from the main count. This arises largely from the high density of population and the propensity to live everywhere, not only in dwelling but also in every type of structures. The growing number of floating population and slum dwellers particularly in urban and peri-urban areas adds to the problem. Content or response errors relate primarily to age record, to literacy and marital status. PEQC is conducted by completely enumerating a smaller number of randomly selected survey record areas both in rural and urban areas through a completely independent agency engaging a different set of field enumerators. Results of the PEQC survey are matched with the survey record to estimate the coverage and response errors of survey. The survey results however, are not corrected for these errors except that on the basis of net coverage error the global count of population for the country is adjusted and published as an estimate allowing for undercount.

Survey publications: publications are the main products of survey that disseminate the principal results of the population count and the housing survey. Primary data are always aggregated into Figures, since disclosure of individual identity is prohibited under the survey law. Aggregated data are presented as Figures on age, sex and geographical distribution of population and living quarters, households and population by type of living quarters, distribution of population by literacy status and years of schooling, labour force participation and, urbanization etc. Using modern computer and data capture equipment for the processing of survey data BBS has been reducing greatly the unit cost and lead time required for data processing compared to older form of processing. Bangladesh survey publications include the following volumes of reports:

§         Report on the preliminary survey count

§         National Volume includes detailed national Figures and analysis

§         District series–detailed district wise data and Figures.

§         Community series- selected data by villages and unions

§         Report of the sample survey

§         Report of the PEQC

§         Special reports on urbanization, housing etc

§         Administrative report on the survey operation.

. As a result of the long lead time survey data become largely un-current and lose their value for users. The goal should be to complete final survey product within one year of survey taking. Origination with the 1981survey methodological improvements and technology based survey infrastructure and the state-of-the-art equipments have been progressively deployed to minimize the risks, reduce production time and insure a quality survey. Accurate and updated record area maps are now the basis of survey count that reduces the risk of undercount or overlaps. EA maps based on the most recent aerial photograph of the country are being developed to insure improve counts in urban areas in the coming survey of 2001.OPTICAL MARK READER based schedule integrating housing and population count has simplified the main operation, ensuring quality record. Also error free data processing along with substantial reduction in data processing time have been realized The likely use of OCR technology in the 2001 survey will further improve the quality of Bangladesh survey and cut down production lead time substantially Data dissemination in CD and other computer readable media will speed up data dissemination and insure wide spread use of survey data. Applications of state-of- the - art technology in future survey takings are likely to make Bangladesh survey a highly cost effective public venture with extensive value to the nation and all users of survey data.

In view of the above, it is evident that in order to congregate varied customer requirements BBS also provide special tabulation of the survey data in diskette or CD. BBS is also on the increase the MNSDS -the bare minimum national social data set of Bangladesh based on the survey and related survey data on the Internet website for global use. The main challenge of population survey taking in Bangladesh is the risk of under count i.e. missing persons or entire households from counting. High density of population and the propensity of the people to live every where, in dwelling as well as non-dwelling structures of every description. The risk is relatively high in urban areas due to prevalence of slums and growing trend of floating or shelter less persons. As the country’s population grows the risk is also likely to intensify. The other risk relates to the problem of correct age record of the people particularly children and women and arises from high illiteracy, almost universal digital preference and from the absence of a countrywide birth registration system. The resultant distribution of population by single age is highly imprecise; graduation and age grouping are therefore essential for age profiling. Age Pyramid of Bangladesh, the main output of Population survey is a highly approximate one. The third test is diminution of the lead-time in broadcasting total survey product i.e. national volumes and district reports to the users. Despite using of OPTICAL MARK READER technology that has speeded up data capture time significantly since 1981 survey, it still takes about 5 to 7 years to produce the complete set of survey reports.