The 1996 Uzbekistan Demographic and Health Survey (UDHS) is a nationally representative survey of 4,415 women age 15-49. Fieldwork was conducted from June to October 1996. The UDHS was sponsored by the Ministry of Health (MOH), and was funded by the United States Agency for International Development. The Institute of Obstetrics and Gynecology implemented the survey with technical assistance from the Demographic and Health Surveys (DHS) program.
The 1996 UDHS was the first national-level population and health survey in Uzbekistan. It was implemented by the Research Institute of Obstetrics and Gynecology of the Ministry of Health of Uzbekistan. The 1996 UDHS was funded by the United States Agency for International development (USAID) and technical assistance was provided by Macro International Inc. (Calverton, Maryland USA) through its contract with USAID.
OBJECTIVES AND ORGANIZATION OF THE SURVEY
The purpose of the 1996 Uzbekistan Demographic and Health Survey (UDHS) was to provide an information base to the Ministry of Health for the planning of policies and programs regarding the health of women and their children. The UDHS collected data on women's reproductive histories, knowledge and use of contraception, breastfeeding practices, and the nutrition, vaccination coverage, and episodes of illness among children under the age of three. The survey also included, for all women of reproductive age and for children under the age of three, the measurement of the hemoglobin level in the blood to assess the prevalence of anemia and measurements of height and weight to assess nutritional status.
A secondary objective of the survey was to enhance the capabilities of institutions in Uzbekistan to collect, process and analyze population and health data so as to facilitate the implementation of future surveys of this type.
- Fertility Rates. Survey results indicate a total fertility rate (TFR) for all of Uzbekistan of 3.3 children per woman. Fertility levels differ for different population groups. The TFR for women living in urbml areas (2.7 children per woman) is substantially lower than for women living in rural areas (3.7). The TFR for Uzbeki women (3.5 children per woman) is higher than for women of other ethnicities (2.5). Among the regions of Uzbekistan, the TFR is lowest in Tashkent City (2.3 children per woman).
- Family Planning. Knowledge. Knowledge of contraceptive methods is high among women in Uzbekistan. Knowledge of at least one method is 89 percent. High levels of knowledge are the norm for women of all ages, all regions of the country, all educational levels, and all ethnicities. However, knowledge of sterilization was low; only 27 percent of women reported knowing of this method.
- Fertility Preferences. A majority of women in Uzbekistan (51 percent) indicated that they desire no more children. Among women age 30 and above, the proportion that want no more children increases to 75 percent. Thus, many women come to the preference to stop childbearing at relatively young ages when they have 20 or more potential years of childbearing ahead of them. For some of these women, the most appropriate method of contraception may be a long-acting method such as female sterilization, However, there is a deficiency of both knowledge and use of this method in Uzbekistan. In the interest of providing couples with a broad choice of safe and effective methods, information about this method and access to it should be made available so that informed choices about its suitability can be made by individual women and couples.
- Induced Aboration : Abortion Rates. From the UDHS data, the total abortion rate (TAR)--the number of abortions a woman will have in her lifetime based on the currently prevailing abortion rates--was calculated. For Uzbekistan, the TAR for the period from mid-1993 to mid-1996 is 0.7 abortions per woman. As expected, the TAR for Uzbekistan is substantially lower than recent estimates of the TAR for other areas of the former Soviet Union such as Kazakstan (1.8), Romania (3.4 abortions per woman), and Yekaterinburg and Perm in Russia (2.3 and 2.8, respectively).
- Infant mortality : In the UDHS, infant mortality data were collected based on the international definition of a live birth which, irrespective of the duration of pregnancy, is a birth that breathes or shows any sign of life (United Nations, 1992).
- Mortality Rates. For the five-year period before the survey (i.e., approximately mid- 1992 to mid- 1996), infant mortality in Uzbekistan is estimated at 49 infant deaths per 1,000 births. The estimates of neonatal and postneonatal mortality are 23 and 26 per 1,000.
- Maternal and child health : Uzbekistan has a well-developed health system with an extensive infrastructure of facilities that provide maternal care services. This system includes special delivery hospitals, the obstetrics and gynecology departments of general hospitals, women's consulting centers, and doctor's assistant/midwife posts (FAPs). There is an extensive network of FAPs throughout rural areas.
- Nutrition : Breastfeeding. Breastfeeding is almost universal in Uzbekistan; 96 percent of children born in the three years preceding the survey are breastfed. Overall, 19 percent of children are breastfed within an hour of delivery and 40 percent within 24 hours of delivery. The median duration of breastfeeding is lengthy (17 months). However, durations of exclusive breastfeeding, as recommended by WHO, are short (0.4 months).
- Prevalence of anemia : Testing of women and children for anemia was one of the major efforts of the 1996 UDHS. Anemia has been considered a major public health problem in Uzbekistan for decades. Nevertheless, this was the first anemia study in Uzbekistan done on a national basis. The study involved hemoglobin (Hb) testing for anemia using the Hemocue system.
Women. Sixty percent of the women in Uzbekistan suffer from some degree of anemia. The great majority of these women have either mild (45 percent) or moderate anemia (14 percent). One percent have severe anemia.
Kind of data
Sample survey data
Seven raions were excluded from the survey because they were considered too remote and sparsely inhabited.
Unit of analysis
- Women age 15-49
The population covered by the 1996 UDHS is defined as the universe of all women age 15-49 in Uzbekistan
Producers and sponsors
Institute of Obstetrics & Gynecology
Ministry of Health (MOH)
Macro International Inc.
U.S. Agency for International Development
The UDHS employed a probability sample of women age 15 to 49, representative of 98.7 percent of the country. Seven raions were excluded from the survey because they were considered too remote and sparsely inhabited. These raions are: Kungradskiyi, Muyinakskiyi, and Takhtakupyrskiyi in Karakalpakstan; Uchkudukskiyi, Tamdynskiyi, and Kanimekhskiyi in Navoiiskaya; and Romitanskiyi in Bukharskaya. The remainder of the country was divided into five survey regions. Tashkent City constituted a survey region by itself, while the remaining four survey regions consisted of groups of contiguous oblasts. The five survey regions were defined as follows:
Region 1: Karakalpakstan and Khoresmskaya.
Region 2: Navoiyiskaya, Bukharskaya, Kashkadarinskaya, and Surkhandarinskaya.
Region 3: Samarkandskaya, Dzhizakskaya, Syrdarinskaya, and Tashkentskaya.
Region 4: Namanganskaya, Ferganskaya, and Andizhanskaya.
Region 5: Tashkent City.
CHARACTERISTICS OF THE UDHS SAMPLE
The sample for the UDHS was selected in three stages. In the rural areas, the primary sampling units (PSUs) corresponded to the raions which were selected with probabilities proportional to size, the size being the 1994 population. At the second stage, one village was selected in each selected raion. A complete listing of the households residing in each selected village was carried out. The lists of households obtained were used as the frame for third-stage sampling, which is the selection of the households to be visited by the UDHS interviewing teams during the main survey fieldwork. In each selected household, women between the ages of 15 and 49 were identified and interviewed.
In the urban areas, the PSUs were the cities and towns themselves. In the second stage, one health block was selected from each town except in self-representing cities (large cities that were selected with certainty), where more than one health block was selected. The selected health blocks were segmented prior to the household listing operation which provided the household lists for the third-stage selection of households.
The regions, stratified by urban and rural areas, were the sampling strata. There were thus nine strata with Tashkent City constituting an entire stratum. A proportional allocation of the target number of 4,000 women to the 9 strata would yield the sample distribution.
The proportional allocation would result in a completely self-weighting sample but would not allow for reliable estimates for at least two of the five survey regions, namely Region 1 and Tashkent City. Results of other demographic and health surveys show that a minimum sample of 1,000 women is required in order to obtain estimates of fertility and childhood mortality rates at an acceptable level of sampling errors. Given that the total sample size for the UDHS could not he increased so as to achieve the required level of sampling errors, it was decided that the sample would be divided equally among the five regions, and within each region, it would be distributed proportionally to the urban and the rural areas. With this type of allocation, demographic rates (fertility and mortality) could not be produced for regions separately.
The number of sample points (or clusters) to be selected for each stratum was calculated by dividing the number of women in the stratum by the average "take" in the cluster. Analytical studies of surveys of the same nature suggest that the optimum number of women to be interviewed is around 20-25 in each urban cluster and 30-35 in each rural cluster. If, on average, 20 women in each urban cluster and 30 women in each rural cluster were to be interviewed, then the distribution of sample points would be shown as follows:
Table Number of sample points
Region 1 32
Region 2 30
Region 3 31
Region 4 31
Tashkent City 40
The number of clusters in Region 2 would yield a slightly smaller number of women than expected because of rounding errors. Consequently, the number of clusters was rearranged in each stratum to be an even number, but in such a way that the expected regional sample size did not fall short of the required 800 minimum. The even number of clusters is recommended for the purpose of calculating sampling errors in which the first step is to form pairs of homogeneous clusters.
The number of households to be selected for each stratum was calculated as follows: Number of women Number of HHs = Number of women per HH x Overall response rate
According to the 1989 census, the proportion of women age 15-49 in Uzbekistan was 25.0 percent in the urban areas and 22.3 percent in the rural areas. By applying this figure to the average household size of 4.7 and 6.2 for the urban and rural areas, respectively, obtained from the census, the number of women age 15-49 was estimated to be 1.2 per urban household and 1.4 per rural household. The overall response rate was assumed to be 80 percent (95 percent for households and 85 percent for women), which was the average overall response rate found in other surveys implemented in Uzbekistan. Using these two parameters in the above equation, approximately 3,900 households had to be selected in order to yield the target sample of women. This resulted in selecting on average 21 households in each urban cluster and 27 households in each rural cluster.
A total of 3,945 households were selected in the sample, of which 3,763 were occupied at the time of conducting fieldwork. The main reason for the difference was that some dwelling units which were occupied at the time of the household listing operation were either vacant or members of the household were away for an extended period at the time of interviewing. Of the 3,763 occupied households, 3,703 were interviewed, yielding a household response rate of 98 percent.
In the interviewed households, 4,544 women were eligible for the individual interview (i.e., all women 15-49 years of age who were either usual residents or visitors who had spent the previous night in the household). Interviews were completed with 4,415 of these women, yielding a response rate of 97 percent. The principal reason for nonresponse was a failure to find an eligible woman at home after repeated visits to the household. The overall response rate for the survey, the product of the household and the individual response rates, was 96 percent.
2 - Individual interviews
Number of eligible women: 4,544
Number of eligible women interviewed: 4,415
Eligiblewoman response rate: 97.2%
Dates of collection
Mode of data collection
Two questionnaires were used for the UDHS: a) the Household Questionnaire and b) the Individual Questionnaire. The questionuaires were based on the model survey instruments developed in the DHS program. The questionnaires were adapted to the data needs of Uzbekistan during consultations with specialists in the areas of reproductive health and child health in Uzbekistan. Both questionnaires were developed in English and then translated into Russian and Uzbek. A pretest was conducted in March-April 1996. Based on the pretest experience, the questionnaires were further modified.
a) The Household Questionnaire was used to enumerate all usual members and visitors in a sample household and to collect information relating to the characteristics of the dwelling unit. In the first part of the Household Questionnaire, information was collected on age, sex, educational attainment, and relationship to the head of household of each person listed as a household member or visitor. The primary objective of collecting this information was to identify women who were eligible for the individual interview. In the second part of the Household Questionnaire, questions were included on the dwelling unit, such as number of rooms, flooring material, source of water, type of toilet facilities, and on the availability of a variety of consumer goods.
b) The Individual Questionnaire was used to collect information from women age 15-49. These women were asked questions on the following major topics:
- Background characteristics
- Pregnancy history
- Pregnancy outcome and antenatal care
- Child health and nutrition practices
- Child immunization and episodes of diarrhea and respiratory illness
- Knowledge and use of contraception
- Marriage and fertility preferences
- Husband's background and woman's work experience
- Maternal and child anthropometry
- Hemoglobin measurement of women and children
One of the major efforts of the UDHS was testing women and children for anemia. Testing was done by measuring hemoglobin levels in the blood, using a portable machine called a Hemocue. Before collecting the blood sample, women were asked to sign a consent form, giving permission for the collection of a blood droplet from herself and her children. Results of anemia testing were kept confidential (as are all UDHS data); however, strictly with the consent of respondents, local health care facilities were informed of women who had severely low levels of hemoglobin (less than 7 g/dl).
Questionnaires were returned to the Institute of Obstetrics and Gynecology in Tashkent for data processing. The office editing staff checked that questionnaires for all selected households and eligible respondents were returned from the field. The few questions which had not been precoded (e.g., occupation, type of chronic disease) were coded at this time. Data were then entered and edited on microcomputers using the ISSA (Integrated System for Survey Analysis) package, with the data entry software translated into Russian. Office editing and data entry activities began on August 5, and were completed on October 31, 1996.
Sampling errors, on the other hand, can be evaluated statistically. The sample of respondents selected in the UDHS 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 differ somewhat from the results of the actual sample selected. Sampling errors are 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.
A sampling error is usually measured in terms of the standard error for a particular statistic (mean, percentage, etc.), which is the square root of the variance. 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 respondents had been selected as a simple random sample, it would have been possible to use straightforward formulas for calculating sampling errors. However, the UDHS sample is the result of a multistage stratified design, and, consequently, it was necessary to use more complex formulae. The computer software used to calculate sampling errors for the UDHS is the ISSA Sampling Error Module. This module used the Taylor linearization method of variance estimation for survey estimates that are means or proportions. The Jackknife repeated replication method is used for variance estimation of more complex statistics such as fertility and mortality rates.
The Jackknife repeated replication method derives estimates of complex rates from each of several replications of the parent sample, and calculates standard errors for these estimates using simple formulae. Each replication considers all but one clusters in the calculation of the estimates. Pseudo-independent replications are thus created. In the UDHS, there were 168 non-empty clusters. Hence, 168 replications were created.
In addition to the standard error, ISSA computes the design effect (DEFT) for each estimate, which is defined as the ratio between the standard error using the given sample design and the standard error that would result ifa 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, while a value greater than 1.0 indicates the increase in the sampling error due to the use of a more complex and less statistically efficient design. ISSA also computes the relative error and confidence limits for the estimates.
Sampling errors for the UDHS are calculated for selected variables considered to be of primary interest. The results are presented in an appendix to the Final Report for the country as a whole, for urban and rural areas, and for five survey regions. For each variable, the type of statistic (mean, proportion, or rate) and the base population are given in Table B.1 of the Final Report. Tables B.2 to B.9 present the value of the statistic (R), its standard error (SE), the number of unweighted (N) and weighted (WN) cases, the design effect (DEFT), the relative standard error (SE/R), and the 95 percent confidence limits (R±2SE) for each variable. The DEFT is considered undefined when the standard error considering simple random sample is zero (when the estimate is close to 0 or 1). Estimates and sampling errors of total fertility and childhood mortality rates only apply to the national sample and the urban and rural samples. In the case of the total fertility rate, tbe number of unweighted cases is not relevant, as there is no known unweighted value for woman-years of exposure to childbearing.
The confidence interval (e.g., as calculated for Children ever born to women age 15-49) can be interpreted as follows: the overall average from the national sample is 2.26 and its standard error is .045. Therefore, to obtain the 95 percent confidence limits, one adds and subtracts twice the standard error to the sample estimate, i.e., 2.26±2x.045. 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 2.17 and 2.35. Sampling errors are analyzed for the national sample and for two separate groups of estimates: (1) means and proportions, and (2) complex demographic rates. The relative standard errors (SE/R) for the means and proportions range between 0 percent and 33.3 percent with an average of 6.7 percent; the highest relative standard errors are for estimates of very low values (e.g., Severe anemia among children under three who were tested). If estimates of very low values (less than 10 percent) were removed, than the average drops to 4.1 percent. So in general, the relative standard errors for most estimates for the country as a whole are small, except for estimates of very small proportions. The relative standard error for the total fertility rate is small at 3.9 percent. However, for the mortality rates, the average relative standard error is much higher at 15.7 percent.
There are differentials in the relative standard error for the estimates of sub-populations. For example, for the variable secondary-special education, the relative standard errors as a percent of the estimated proportion for the whole country, for the rural areas, and for Region 2 are 4.3 percent, 7.8 percent, and 11.4 percent, respectively. For the total sample, the value of the design effect (DEFT), averaged over all variables, is 1.36 which means that, due to multistage clustering of the sample, variance is increased by a factor of 1.8 over that in an equivalent simple random sample.
Other forms of data appraisal
Nonsampling errors are the results of 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 during the implementation of the UDHS to minimize this type of error, nonsampling errors are impossible to avoid and difficult to evaluate statistically.
Use of the dataset must be acknowledged using a citation which would include:
- the Identification of the Primary Investigator
- the title of the survey (including country, acronym and year of implementation)
- the survey reference number
- the source and date of download
Disclaimer and copyrights
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.