TUR_1993_DHS_v01_M
Demographic and Health Survey 1993
Name | Country code |
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Turkiye | TUR |
Demographic and Health Survey (standard) - DHS III
The Turkish Demographic and Health Survey 1993 is the first survey of its kind to be conducted in Turkey.
Sample survey data
The Turkish Demographic and Health Survey 1993 covers the following topics:
The Turkish Demographic and Health Survey (TDHS) is a national sample survey.
The population covered by the 1993 DHS is defined as the universe of all ever-married women age 12-49 who were present in the household on the night before the interview were eligible for the survey.
Name | Affiliation |
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Institute of Population Studies | Hacettepe University |
General Directorate of Mother and Child Health and Family Planning | Ministry of Health |
Name | Role |
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Macro International Inc. | Technical assistance |
Name | Role |
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U.S. Agency for International Development | Funding |
The sample for the TDHS was designed to provide estimates of population and health indicators, including fertility and mortality rates for the nation as a whole, fOr urban and rural areas, and for the five major regions of the country. A weighted, multistage, stratified cluster sampling approach was used in the selection of the TDHS sample.
Sample selection was undertaken in three stages. The sampling units at the first stage were settlements that differed in population size. The frame for the selection of the primary sampling units (PSUs) was prepared using the results of the 1990 Population Census. The urban frame included provinces and district centres and settlements with populations of more than 10,000; the rural frame included subdistricts and villages with populations of less than 10,000. Adjustments were made to consider the growth in some areas right up to survey time. In addition to the rural-urban and regional stratifications, settlements were classified in seven groups according to population size.
The second stage of selection involved the list of quarters (administrative divisions of varying size) for each urban settlement, provided by the State Institute of Statistics (SIS). Every selected quarter was subdivided according tothe number of divisions(approximately 100 households)assigned to it. In rural areas, a selected village was taken as a single quarter, and wherever necessary, it was divided into subdivisions of approximately 100 households. In cases where the number of households in a selected village was less than 100 households, the nearest village was selected to complete the 100 households during the listing activity, which is described below.
After the selection of the secondary sampling units (SSUs), a household listing was obtained for each by the TDHS listing teams. The listing activity was carried out in May and June. From the household lists, a systematic random sample of households was chosen for the TDHS. All ever-married women age 12-49 who were present in the household on the night before the interview were eligible for the survey.
The results of sample implementation for the household and the individual interviews for the country as a whole, for urban and rural areas, and for the five regions of Turkey. The results indicate that of the 10,631 households selected, the TDHS fieldwork teams successfully completed interviews with 8,619 (81 percent). The main reasons fieldwork teams were unable to interview some households were that some of the listed dwelling units were found to be vacant at the time of the interview or the household was away for an extended period. Eight thousand nine hundred households were identified as being occupied, and 8,619 households were successfully interviewed. Consequently, the household response rate was calculated as 96.8 percent. The household response rate was higher in rural areas than in urban areas and highest in the Southern and Northern regions.
In the interviewed households, 6,862 eligible women were identified, of whom 95 percent were interviewed. Eligibility for the individual interview required that the woman be ever-married, be younger than 50 years of age, and be present in the household on the night before the interview. Among the small number of eligible women not interviewed in the survey, the principal reason for nonresponse was the failure to find the woman at home after repeated visits to the household. The eligible woman response rate was higher in rural areas than in urban areas and was higher in the Southern and Central regions than in the other three regions.
The overall response rate for the TDHS was calculated as 92 percent, ranging from 89 percent in the Eastern region to 95 percent in the Southern region.
Analysis has to be performed using weights. As mentioned earlier, the TDHS sampling plan is not a self-weighted one; in order to have sufficient numbers of observations for meaningful statistical analyses, more sample units were chosen from the Northern and Southern regions, which would have yielded inadequate numbers of observations if the target number of households had been allocated by PPS.
The number of households that were selected in each region according to power allocation as well as the expected numbers of households assuming a PPS distribution of the targeted 10,000 households can be seen in Table B.I of the Final Report.
The weight assigned to any stratum is simply the reciprocal of the sampling fraction employed in calculating the number of units in that particular stratum:
w (i) = / f (i) .
The term f(i), the sampling fraction at the i 'h stratum, is the product of the probabilities of selection at every stage in a stratum:
f (i) = P (i,l) P (i,2) ...... * P (i,s) where s is the stage.
The weights for the regions were assumed to be compensated for the nonresponse to the Household Questionnaire and to the Individual Questionnaire during fieldwork. The compensating factor for the nonresponse for the Household Questionnaire is the inverse value of:
R (i,2) = Completed households/Eligible households.
Eligible households include the households where interviews were completed, households where there were no competent respondents, households where interviews were postponed and eventually not completed, refusals, and those dwellings.that were not found by the fieldwork teams.
Similarly, the compensating factor for the nonresponse to the Individual Questionnaire is the inverse value of:
R (i,3) = Completed individual questionnaires/Eligible women.
Since selection was carried out proportionately in the urban/rural breakdown within the regions, and since there is almost no variation in nonresponse rates among the rural areas of the five regions, there was no need to calculate separate weights for rural and urban areas.
Weights should also include compensating factors for the missing clusters that were not visited at all for various reasons. Since sample selection was done in subregions, it would be better to have compensating factors in the subregional level.
The weights for the households were calculated by multiplying the above factors for each region and subregion. They were then standardized by multiplying these weights by the ratio of the number of interviewed households to the total weighted number of households. Standardization of the weights of individual women was undertaken by multiplying the individual weights by the ratio of the number of interviewed women to the total weighted number of women.
Two questionnaires were used in the main fieldwork for the TDHS: the Household Questionnaire and the Individual Questionnaire for ever-married women of reproductive age. The questionnaires were based on the model survey instruments developed in the DHS program and on the questionnaires that had been employed in previous Turkish population and health surveys. The questionnaires were adapted to obtain data needed for program planning in Turkey during consultations with population and health agencies. Both questionnaires were developed in English and translated into Turkish.
a) The Household Questionnaire was used to enumerate all usual members of and visitors to the selected households and to collect information relating to the socioeconomic position of the households. In the first part of the Household Questionnaire, basic information was collected on the age, sex, educational attainment, marital status and relationship to the head of household for each person listed as a household member or visitor. The objective of the first part of the Household Questionnaire was to obtain the information needed to identify women who were eligible for the individual interview as well as to provide basic demographic data for Turkish households. In the second part of the Household Questionnaire, questions were included on the dwelling unit, such as the number of rooms, the flooring material, the source of water, and the type of toilet facilities, and on the household's ownership of a variety of consumer goods.
b) The Individual Questionnaire for women covered the following major topics:
The woman's questionnaire included a monthly calendar, which was used to record fertility, contraception, postpartum amenorrhea and abstinence, breastfeeding, marriage, and migration histories for periods of more than five years, beginning in January 1988, up to the survey month. In addition, the fieldwork teams measured the heights and weights of children under age five and of their mothers, as well as mothers' as circumference.
Start | End |
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1993-08 | 1993-10 |
Name |
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Hacettepe Institute of Population Studies |
LISTING AND MAPPING ACTIVITIES
The SIS prepared the household urban frame in Turkey that could be used for sampling purposes. The frame was created in April 1989 during the preparations for the 1990 Population Census. It contained a list of dwelling units with their full addresses (quarter, area, avenue, street, building and door number, etc.). The frame was created by a quick count of buildings; however, the quality ofthe resulting lists varied primarily due to two reasons: first, the quality of work produced by the listers varied across listing teams, and second, circumstances in some areas of Turkey allowed listers to produce detailed lists of quarters, but other areas were very restrictive in the quality of work to be produced.
Although the SIS had a set of dwelling lists, they did not have the corresponding maps. For this reason, the selected clusters were formed with streets that were not always adjacent to each other. The cluster (standard segment) size was around 100 households for most of the clusters in urban areas. Only two urban clusters had extremely high numbers of households; these were truncated at 200 households.
The lists provided by the SIS did not reflect the changes that may have occurred during the period from the 1990 Population Censusto the survey date. Two types of changes were possible: those that could be updated during listing, such as the construction of a new building on the street, a change in the use of a building (e.g., a fiat can be used as an office instead of a dwelling), or changes in the names of streets, and those that were more problematic, e.g., the appearance of new quarters in urban centres. The latter places had a probability of zero of being selected to the TDHS sample since they were not included in the SIS lists.
An attempt to identify the possible problems that could arise during the actual listing work was made by undertaking a listing activity in the capital, Ankara, before the actual listing activity began. Listing forms and listing and mapping manuals were developed based on this experience.
Listing teams were formed following a four-day training program in May 1993. Each team was provided with the necessary materials, as well as with maps describing the location of the settlements they were expected to visit.
The performance of the listers was supervised by research assistants of the Hacettepe Institute of Population Studies. More than 60 percent of the clusters in the sample were listed under the supervision of the research assistants.
In 15 of the selected 198 villages, the total populations were too small, and therefore did not yield the standard segment size of 100 households. In these cases, the village that was nearest to the selected village was also included in the sample, and the names of these villages were provided to the listing teams; the lists of 100 households were completed from the two villages.
Most of the listing activity was completed before the training for the main fieldwork began in July; however, listing of 25 clusters was completed independently by separate listing teams atter the main fieldwork began. A number of clusters could not be listed due to problems of accessibility;
PRETEST
In May 1993, a pretest was conducted to ensure that the questions in the TDHS questionnaires were in a logical sequence; that the wording of the questions was comprehensible, appropriate and meaningful; and that the precoded answers were adequate.
Fifteen interviewers were trained at the Hacettepe Institute of Population Studies for a period of two weeks. The training period included both classroom training and interviews in the field. The interviewers were mostly university graduates who had worked on previous surveys. In addition to the interviewers, research assistants, who would later become regional coordinators and supervisors, also received training.
Fieldwork for the pretest was carried out in one district in central Ankara, two districts in squatter housing areas of Ankara, and a village in Ankara province. Notebook computers were used by the research assistants to enter data in the field.
Some 180 interviews were completed during the pretest. Frequency distributions and cross tabulations were obtained shortly after the completion of the interviews. Based on the evaluation of these results and on the feedback obtained from the interviewers, several minor changes were made to the TDHS questionnaires.
STAFF RECRUITMENT
Candidates for the positions of interviewers, field editors, supervisors and measurers were solicited from newspaper advertisements and Institute of Population Studies files of field editors and supervisors who had worked on previous surveys. All candidates for the field staff positions were interviewed in three groups by the staff of the Institute of Population Studies using interview guidelines prepared for this purpose. Individuals who met a number of the requirements and had the necessary qualifications were accepted into the training program.
All candidates for the field staff positions were at least high school graduates and the majority were university students. Previous survey experience was not among the qualifications for the candidates for the position of interviewers to ensure that the trainees had no biases that might result from their previous experience. Approximately 120 applicants were accepted for the training program.
TRAINING
Training of the candidates for the fieldwork positions began on 19 July 1993 at the Hacettepe Institute of Population Studies. The training program included general lectures related to the demographic situation in Turkey, family planning and mother and child health, questionnaire training, role playing and mock interviews, field practice in areas not covered in the survey and quizzes to test the progress and capabilities of the candidates. A variety of materials were used during the training sessions, including manuals for supervisors and editors, and for interviewers.
All trainees received the same classroom training during the first two weeks of the training period; at the beginning of the third week, supervisors, field editors, and measurers were selected from among the candidates, and a number of unsuccessful candidates were eliminated at this stage. Separate classroom training sessions were organised for supervisors, field editors, and measurers. Towards the end of the third week of the training program, teams that would eventually participate in the main fieldwork were selected. Six field editors were randomly selected to do data entry and editing in the field using notebook-type computers and were trained separately for this purpose. The training program continued for about 20 days.
FIELDWORK
Fieldwork for the TDHS, including initial interviews, callbacks and reinterviews began in the first week of August 1993 and was completed at the end of October 1993.
Fieldwork activities were completed in two stages. In the first stage, data collection was carried out by 13 teams, each consisting of a supervisor, a field editor, a measurer and 4 or 5 interviewers, depending on the workload of that specific team. All teams worked in Ankara in the beginning and as soon as all initial visits to all the selected households were completed they left for the other provinces.
The first stage of the fieldwork was completed by the end of September, at which point a number of fieldwork staff, as agreed initially, discontinued working in the field. Four new teams were set up from among the 13 teams who worked in the first stage of fieldwork. The teams at this second stage had the same composition as those in the first stage but only one team used a notebook to enter and edit data rather than five in the first stage. This stage continued until the end of October.
Four regional coordinators were responsible for visiting the fieldwork teams in turn, checking the quality of data collected, and reporting periodically to the field director in Ankara. All interviewers and field editors were female and all measurers were male; both male and female supervisors were present.
Fieldwork teams visited 68 of the 76 provinces in Turkey. Some 41 percent of the clusters in the sample were from provincial centres, 21 percent were from district centres, and 38 percent were from subdistrict centres and villages. The TDHS fieldwork was a relatively fast operation because of the specific conditions prevailing in the country, i.e., a large proportion of the fieldwork staffconsisted of students who had to begin school in October and climatic conditions in many parts of the country limited access to many areas after October.
A total of 500 clusters were selected for the TDHS sample. Of these, interviews were successfully completed in 478 clusters. Due to accessiblity problems and lack of security, 8 clusters were not listed and consequently were not visited by the fieldwork teams; 14 clusters were listed but fteldwork teams could not visit them because of the problems mentioned before.
Office Editing. The questionnaires were returned to the Institute of Population Studies by the fieldwork teams for data processing as soon as each provincial interview was completed. The office editing staff checked that the questionnaires for all the selected households and eligible respondents were returned from the field. The comparatively few questions that had not been precoded (e.g., occupation) were coded at this time.
Machine Entry and Editing. The data were entered and edited on microcomputers using the Integrated System for Survey Analysis (ISSA), a packaged program specifically developed to process DHS data. ISSA allows range, skip, and consistency errors to be detected and corrected at the data entry stage. The machine entry and editing activities were initiated within two days after the beginning of the fieldwork and were completed 10 days after the completion of the fieldwork. Advantage was taken of the fact that data processing activities ran concurrently with fieldwork. Field check tables from edited data were periodically produced for each interviewing team. These focused on such potential problems as high proportions of incomplete households and displacement of eligible respondents and were used to check the progress and quality of data from the field.
The estimates from a sample survey are affected by two types of errors--nonsampling and sampling. Nonsampling errors result from mistakes made in implementing data collection and data processing, such as failure to locate and interview the correct household, misunderstanding of the questions on the part of either the interviewer or the respondent, and data entry errors. Although numerous efforts were made to minimise this type of error during the implementation of the TDHS, nonsampling errors are impossible to avoid and difficult to evaluate statistically.
Sampling errors, on the other hand, can be evaluated statistically. The sample of women selected in the TDHS is only one of many samples that could have been selected from the same population, using the same design and expected size. Each of these samples would yield results that would differ somewhat from the results of the actual sample selected. The sampling error is a measure of the variability between all possible samples. Although the degree of variability is not known exactly, it can be estimated from the survey results.
Sampling error is usually.measured in terms of the standard error for a particular statistic (mean, percentage, etc.), which isthe ratio of the standard deviation to the square root of the sample size. The standard error can be used to calculate confidence intervals within which the true value for the population can reasonably be assumed to fall. For example, for any given statistic calculated from a sample survey, the value of that statistic will fall within a range of plus or minus two times the standard error of that statistic in 95 percent of all possible samples of identical size and design.
If the sample of women had been selected as a simple random sample, it would have been possible to use straightforward formulas for calculating sampling errors. However, the TDHS sample is the result of a three-stage stratified design, and, consequently, it was necessary to use more complex formulas. The computer package CLUSTERS, developed by the International Statistical Institute for the World Fertility Survey, was used to compute the sampling errors for 42 variables with the proper statistical methodology.
The CLUSTERS package treats any percentage or average as a ratio estimate, r = y/x, where y represents the total sample value for variable y, and x represents the total number of cases in the group or subgroup under consideration. The variance of r is computed using the formula given below, with the standard error being the square root of the variance,
var(r) = 1-f mh 2 Zh
x 2 mh-----i i=1 k
in which
Zhi = Yhi-r.Xhi , and Z h = yh-r.xh
In addition to tile standard errors, CLUSTERS computes the design effect (DEFT) for each estimate, which is defined as the ratio of the standard error using the given sample design to the standard error that would result if a simple random sample had been used. A DEFT value of 1.0 indicates that the sample design is as efficient as a simple random sample, whereas a value greater than 1.0 indicates the increase in tile sampling error due to the use of a more complex and less statistically efficient design. CLUSTERS also computes the relative error and confidence limits for the estimates.
The results for the 42 variables mentioned, which are those considered to be of primary interest, are presented in an appendix to the Final Report for the country as a whole, for urban and rural areas, for the five regions, and for age groups. The type of statistic (mean or proportion) and the base population for each variable are given in Table C.1 of the Final Report. Tables C.2 to C.12 present the value of the statistic (R), its standard error (SE), the number of unweighted (N) and weighted (WN) cases, file design effect (DEFT), the relative standard error (SE/R), and the 95 percent confidence limits (R_+2SE), for each variable.
Additionally, sampling errors were calculated for tile total fertility rote of the last year prior to the survey date and the infant mortality rate for the 5 years preceding the survey, for the national total, and for urban-rural areas. These calculations were undertaken using the Jacknife methodology rather than the CLUSTERS package because of the nature of these two estimates. The Jacknife methodology is based on having replicate values for the estimates and applying the sim pie standard error formulae to these replicates.
Tile TDHS included 478 clusters. Each replication considers all clusters but deletes one cluster at a time for the calculations and then creates pseudoindependent replicates. In total, 478 replications for the infant mortality and total fertility rates create tile pseudoindependent values:
e(.i) = 478 estimate (all clusters) - 477 estimate (all minus i ~h)
e estimate (all clusters)
and tile sampling errors for the estimate is given by:
SE (estimate) = {5-(e(.i) -e)-" / (478 * (478-1)) }'/2.
The results of the calcnlations using the Jacknife methodology to estimate sampling errors for the infant mortality rate and tile total fertility rate for the national total, for urban and rural areas, and for the five major regions is shown in Table C.13 of the Final Report.
Tile confidence interval (e.g., as calculated for EVBORN) can be interpreted as follows: the overall average from the national sample is 3.041 and the standard error is 0.044. Therefore, to obtain the 95 percent confidence limits, one adds and subtracts twice the standard error to the sample estimate, i.e., 3.041 _+ 0.088. There is a high probability (95 percent) that the true average number of children ever born to all women age 15 to 49 is between 2.954 and 3.128.
Of the 42 variables for which CLUSTERS was used for the estimation of sampling errors, 28 are based on women, and 14 are based on children under age 5. Ill general, the relative standard error for most estimates for the country as a whole is small, except for estimates of very small proportions. There are some differentials in the relative standard error for the estimates of subpopulations such as urban and rural areas. For example, for the variable SECATT (secondary school attendance), the relative standard errors as a percent of the estimated proportion for urban and rural areas are 4.6 percent and 12.5 percent, respectively. The same istrue for SECGRD(proportion of women who completed secondary school) with values of 5 percent and 14.2 percent, for XCUPIL (current use of the pill) with values of 8.1 and 13.6 percent, for XCUIUD (current use of IUD) with values of 3.4 and 8.5 percent, and for XCUPAB (current use of periodic abstinence) with values of 17 percent and 0 percent, for urban and rural areas, respectively for each variable. Of the 42 variables, 24 were found to have SE/R values of less than 0.03, which means that the SE of those variables is at most 3 percent of the estimate. SE/R values are between 0.031 and 0.059 for 13 variables, and greater than 0.06 for only 5 variables; the maximum value being 16.6 percent. The variables with the highest SE/R ratio are the ones calculated for relatively rare events.
The DEFT value is less than 1.3 for 24 variables; between 1.31 and 1.5 for 13 variables; and greater than 1.51 for only 5 variables. The maximum DEFT value obtained is 1.668. The average of 42 variables is 1.301. The average is 1.213 in urban areas and 1.293 in rural areas for 41 variables (due to the exclusion of the URBAN variable).
Name | Affiliation | URL | |
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MEASURE DHS | ICF International | www.measuredhs.com | archive@measuredhs.com |
Use of the dataset must be acknowledged using a citation which would include:
The user of the data acknowledges that the original collector of the data, the authorized distributor of the data, and the relevant funding agency bear no responsibility for use of the data or for interpretations or inferences based upon such uses.
Name | Affiliation | URL | |
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General Inquiries | info@measuredhs.com | www.measuredhs.com | |
Data and Data Related Resources | archive@measuredhs.com | www.measuredhs.com | |
Institute of Population Studies | Hacettepe University | hips@hacettepe.edu.tr | http://www.hips.hacettepe.edu.tr/eng/index.html |
DDI_WB_TUR_1993_DHS_v01_M
Name | Role |
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World Bank, Development Economics Data Group | Generation of DDI documentation |
2012-04-11
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