Demographic and Health Survey 1987
Trinidad and Tobago, 1987
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TTO_1987_DHS_v01_M
Demographic and Health Survey 1987
| Name | Country code |
|---|---|
| Trinidad and Tobago | TTO |
Demographic and Health Survey (standard) - DHS I
The Trinidad and Tobago Demographic and Health Survey (TTDHS 1987) is the first national survey of Demographic and Health survey in Trinidad and Tobago.
The sampling frame for the TTDHS was the Continuous Sample Survey of Population (CSSP), an ongoing survey conducted by the Central Statistical Office based on the 1980 Population and Housing Census.
The TTDHS used a household schedule to collect information on residents of selected households, and to identify women eligible for the individual questionnaire. The individual questionnaire was based on DHS's Model "A" Questionnaire for High Contraceptive Prevalence countries, which was modified for use in Trinidad and Tobago. It covered four main areas: (1) background information on the respondent, her partner and marital status, (2) fertility and fertility preferences, (3) contraception, and (4) the health of children.
The short term objective of the Trinidad and Tobago Demographic and Health Survey (TTDHS) is to collect and analyse data on the demographic characteristics of women in the reproductive years, and the health status of their young children. Policymakers and programme managers in public and private agencies will be able to utilize the data in designing and administering programmes.
The long term objective of the project is to enhance the ability of organisations involved in the TTDHS to undertake surveys of excellent technical quality.
Sample survey data
- Household
- Women age 15-49
Scope
The Trinidad and Tobago Demographic and Health Survey 1988 covers the following topics:
- Background information on the woman
- Background information on the partner's woman
- Contraception
- Fertility and Fertility preferences
- Health of children
- Marital status
Coverage
National
The population covered by the 1988 TTDHS is defined as the universe of all women age 15-49.
Producers and sponsors
| Name |
|---|
| Family Planning Association of Trinidad and Tobago |
| Name | Role |
|---|---|
| Institute for Resource Development/Westinghouse | Technical assistance |
| Name | Role |
|---|---|
| U.S. Agency for International Development | Funding |
| Name | Affiliation | Role |
|---|---|---|
| Central Statistical Office | CSO | Technical support on planning the survey and reviewing the questionnaire |
| Ministry of Health | Technical support on planning the survey and reviewing the questionnaire | |
| Government's Population Programm | Technical support on planning the survey and reviewing the questionnaire | |
| Institute for Social and Economic Research | ISER | Technical support on planning the survey and reviewing the questionnaire |
| Pan American Health Organization | WHO | Technical support on planning the survey and reviewing the questionnaire |
| United Nations Economic Commission for Latin America and the Caribbean | UNECLAC | Technical support on planning the survey and reviewing the questionnaire |
| Caribbean Food & Nutrition Institute | CNFD | Technical support on planning the survey and reviewing the questionnaire |
| United Nations Children's Fund | UNICEF | Technical support on planning the survey and reviewing the questionnaire |
Sampling
The sample for the TTDHS was based on the Continuous Sample Survey of Population (CSSP), used by the Central Statistical Office since 1968, and redesigned on the basis of the 1980 Population and Housing Census.
The country is divided into 14 domains of study, comprising a total of 1,638 enumeration districts (EDs). Results from the 1980 Census indicated that some EDs were too large (more than 300 households) and some too small (fewer than 30 households) to be appropriate primary sampling units (PSUs) for the TFDHS. Therefore, the largest units were further subdivided, and the smaller units combined with contiguous ones for the CSSP sample.
The CSSP sample is selected in two stages. In the first, PSUs are systematically selected, with probability proportional to size (size equals the number of households in the PSU). Following an operation to list all households in each selected PSU, individual households are selected, with probability of selection inversely proportional to the PSU's size.
The CSSP grand sample, which provides an overall sampling fraction of one household in forty (1/40) has been divided into 9 sub-samples, each with an overall sampling fraction of one in three-hundred sixty (1/360). Each CSSP survey round, conducted quarterly, uses three of the nine sub-samples, with an overall sampling fraction of one in one-hundred twenty (1/120).
The DHS sample was taken from the CSSP sample selected for the January-March 1987 quarter. The main objectives of the DHS sample were:
- a self-weighting sample of households,
- a sample take in each selected PSU of about 25 women aged 15-49, and
- a total of 4,000 completed interviews with women aged 15-49.
To achieve this sample size, 5,000 households were selected. This figure assumes an average of one eligible woman per household, and 294,400 eligible women nationwide, giving an overall sampling fraction of one in sixty (1/60). It also allows for 10 percent non-response at both the household and the individual interview level, commensurate with CSO experience in similar recent surveys. In total, 178 PSUs were selected throughout Trinidad and Tobago.
4,122 households were successfully interviewed, out of the 4,799 selected for the sample. The household response rate was 94 percent. This represents households for which the interview was successfully completed out of 4,371 households for which an interview could have been conducted. This latter group includes households not interviewed due to the absence of a competent respondent, refusal, or the interviewer not finding the selected household. Among the 677 selected households which were not interviewed, 604 were missed because of contact difficulties: addresses not found, houses vacant, or those in which the occupants were not at home during repeated visits. Fewer than one percent of households refused to be interviewed.
The household questionnaires identified 4,196 women eligible for the individual questionnaire. This figure represents a yield of one eligible woman per household, which was the average expected. Questionnaires were completed for 3,806 women. The response rate at the individual level was 92 percent, which represents the proportion of interviews successfully completed out of the total number of women identified by the household schedule. The overall response rate, the product of response rates at the household and individual levels is 87 percent.
Contact was not made with 199 eligible women, either because the respondent was not at home during any of three visits by the interviewer, or was temporarily away from the household. Sixty-eight cases were missed due to "Other" reasons, and 83 women refused to be interviewed.
The response rates for the urban and rural areas were similar. In the urban areas, the overall response rate was 86 percent, compared with 88 percent for the rural areas.
Survey instrument
The individual questionnaire was based on DHS's Model "A" Questionnaire for High Contraceptive Prevalence countries, which was modified for use in Trinidad and Tobago. It covered four main areas: (1) background information on the respondent, her partner and marital status, (2) fertility and fertility preferences, (3) contraception, and (4) the health of children.
The DHS model "A" questionnaire was adapted for use in Trinidad and Tobago, and pretested during February 1987. Thirteen pretest interviewers were trained for two weeks by FPATI', CSO, and IRD staff, and carded out two days of interviews. The questionnaire was further modified based on pretest results and interviewer comments.
Data collection
| Start | End |
|---|---|
| 1987-05 | 1987-08 |
| Name |
|---|
| Family Planning Association of Trinidad and Tobago |
TRAINING
Female interviewers were trained for the main survey for four weeks during April and May, 1987. Training consisted of two weeks of classroom lectures, discussions, and practice interviews, followed by a written exam. Trainees then worked in teams conducting practice interviews. To ensure proper supervision of interviewers, field personnel were divided into 5 teams, 4 for Trinidad and 1 for Tobago. Teams consisted of 1 supervisor, 1 field editor/anthropometric measurer, and 4 or 5 interviewers.
Supervisors and field editors received special training in their respective duties. The former were taught to read maps and to use the household listings provided by the CSO for each PSU selected in the sample. The latter were trained to scrutinize questionnaires for accuracy, completeness, and consistency.
In addition, supervisors and field editors were gained by IRD's anthropometrist to weigh and measure young children. Trainees were taught to measure children to within 100 grams of their true weight, and 0.5 centimeters of their true length, with the true measure defined by the mean of two measurements performed by the gainer. The precision and accuracy of the measurements were assessed during standardization tests administered at the conclusion of the anthropometric training and again midway through data collection. The former test was administered by IRD's anthropometrist, the latter by a nutritional biochemist from the Ministry of Health.
FIELDWORK
Thirty-three field personnel, including 1 fieldwork coordinator, 5 supervisors, 4 field editors, and 23 interviewers commenced data collection on May 14. Fieldwork required nearly six weeks longer than scheduled. The two main problems were inaccurate maps and lack of adequate transport. Maps were in many cases outdated, and more time was spent locating the selected households than was anticipated. Secondly, lack of adequate transport made it difficult for interviewers to reach their assigned areas.
One result of the transport difficulties was that supervision of teams was at times compromised. Supervisors generally used their own vehicles to transport their team members, and subsequently had less time available for supervision. Since field editors were responsible for weighing and measuring children, the time available for editing was reduced. Field editors often reviewed questionnaires at home during the evenings, precluding sending interviewers back to households when errors were detected. Moreover, the need to make callback visits to weigh and measure children necessitated keeping team members together on weekends, which further slowed fieldwork.
Data processing
The data processing staff consisted of a chief editor, 3 data entry clerks, and a control clerk who logged in questionnaires when they reached the office. All data entry staff completed the main interviewer training, in addition to data processing instruction by IRD staff. Data entry, editing, and tabulations were performed on microcomputers using the Integrated System for Survey Analysis (ISSA) programme, developed by IRD. The system performed range, skip, and consistency checks upon data entry, so that relatively little machine or manual editing was required. The chief editor was responsible for supervising data entry, and for resolving inconsistencies in the questionnaires detected during secondary machine editing.
Data appraisal
Sampling errors, on the other hand, can be evaluated statistically. The sample of women selected in the 'IIDHS is only one of many samples of the same size that could have been drawn from the population using the same design. Each sample would have yielded slightly different results from the sample actually selected. The variability observed among all possible samples constitutes sampling error, which can be estimated from survey results (though not measured exact/y).
Sampling error is usually measured in terms of the "standard error" (SE) of a particular statistic (mean, percentage, etc.), which is the square root of the variance of the statistic across all possible samples of equal size and design. The standard error can be used to calculate confidence intervals within which one can be reasonably sure the true value of the variable for the whole population falls. For example, for any given statistic calculated from a sample survey, the value of that same statistic as measured in 95 percent of all possible samples of identical size and design will fall within a range of plus or minus two times the standard error of that statistic.
If simple random sampling had been used to select women for the TTDHS, it would have been possible to use straightforward formulas for calculating sampling errors. However, the TTDHS sample design used two stages and clusters of households, and it was necessary to use more complex formulas. Therefore, the computer package CLUSTERS, developed for the World Fertility Survey, was used to compute sampling errors.
In addition to the standard errors, CLUSTERS 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 if a simple random sample had been used. A DEFT value of 1 indicates that the sample design is as efficient as a simple random sample; a value greater than 1 indicates that the increase in the sampling error is due to the use of a more complex and less statistically efficient design.
Sampling errors are presented in Table B.1 of the Final Report for 35 variables considered to be of primary interest. Results are presented for the whole country, for urban and rural areas, and for three age groups. For each variable, the type of statistic (mean, proportion) and the base population (e.g., all women, women in union) are given in Table B.1. Table B.2 presents the value of the statistac, R; its standard error, SE; the actual number of cases, N; the DEFT value; and the relative standard error, SE/R for each variable. In addition to these indicators, the 95 percent confidence limits for the statistic, R-2SD and R+2SD, are presented.
In general, the sampling errors for the country as a whole are small, which means that the TTDHS results are reliable. For example, in the whole sample, the survey found that women average 2.059 children ever born; the standard error of this estimate is .037. Therefore, to obtain the 95 percent confidence limit, one adds and subtracts twice the standard error to the sample estimate, i.e., 2.05 + .074. There is a 95 percent chance that the true average number of children ever born to all women 15-49 in Trinidad and Tobago is between 1.985 and 2.134. This same calculation can be performed for all other variables listed.
Data Access
| Name | Affiliation | URL | |
|---|---|---|---|
| MEASURE DHS | ICF International | www.measuredhs.com | archive@measuredhs.com |
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.
Contacts
| Name | URL | |
|---|---|---|
| General Inquiries | info@measuredhs.com | www.measuredhs.com |
| Data and Data Related Resources | archive@measuredhs.com | www.measuredhs.com |
Metadata production
DDI_TTO_1987_DHS_v01_M
| Name | Role |
|---|---|
| World Bank, Development Economics Data Group | Generation of DDI documentation |
2012-04-18