National Panel Survey 2010-2011
Tanzania, 2010 - 2011
National Bureau of Statistics
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September 21, 2020
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September 21, 2020
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Identification
Survey ID Number
TZA_2010-2011_NPS-W2_v01_EN_M_v01_A_OCS
Title
National Panel Survey 2010-2011
Country
| Name | Country code |
|---|---|
| Tanzania | TZA |
Study type
Living Standards Measurement Study [hh/lsms]
Series Information
The 2010.2011 Tanzania National Panel Survey (NPS) is the second in a series of nationally representative household panel surveys that collect information on a wide range of topics including agricultural production, non-farm income generating activities, consumption expenditures, and a wealth of other socio-economic characteristics. Both the first and second rounds of the Tanzania NPS were implemented by the Tanzania National Bureau of Statistics (NBS). The first round of the survey was conducted over twelve months from October 2008 to September 2009. The main fieldwork of the second round of the Tanzania NPS started in October 2010 and completed in September 2011, with specialized tracking teams remaining in the field until November 2011.
Abstract
The main objective of the Tanzania NPS is to provide high-quality household-level data to the Tanzanian government and other stakeholders for monitoring poverty dynamics, tracking the progress of the Mkukuta poverty reduction strategy1, and to evaluate the impact of other major, national-level government policy initiatives. As an integrated survey covering a number of different socioeconomic factors, it compliments other more narrowly focused survey efforts, such as the Demographic and Health Survey on health, the Integrated Labour Force Survey on labour markets, the Household Budget Survey on expenditure, and the National Sample Census of Agriculture. Secondly, as a panel household survey in which the same households are revisited over time, the Tanzania NPS allows for the study of poverty and welfare transitions and the determinants of living standard changes
Kind of Data
Sample survey data [ssd]
Unit of Analysis
Households
Scope
Notes
- HOUSEHOLD: Household Identification, Household Member Roster, Education, Health, Labour, Food Outside the Household, Subject welfare, Government, Food Security, Housing, Water and Sanitation, Food Consumption, Non-Food Expenditures, Household Assets, Assistance and Groups, Credit, Finance, Recent Shocks to HH Welfare, Anthropometry
- AGRICULTURE: Household Roster, Plot Roster, Plot Details, Annual Crops by plot, Annual Crop Production and Sales, Permanent Crops by plot, Permanent crops - production and sales, Out-grower schemes and contract farming, processed agricultural products and agricultural bi-products, livestock, Farm implements and machinery extension
- FISHERY: Survey Information, fisheries Calendar, household labour, Fishing Labour, input, output, Gear Rented out, trading
- COMMUNITY: Community Identification, Survey staff Details, Access to basic services, Investments projects, land use, Agriculture, Demography and family issues, Governance, Water and sanitation, Roster of Community leaders, Market price
- AGRICULTURE: Household Roster, Plot Roster, Plot Details, Annual Crops by plot, Annual Crop Production and Sales, Permanent Crops by plot, Permanent crops - production and sales, Out-grower schemes and contract farming, processed agricultural products and agricultural bi-products, livestock, Farm implements and machinery extension
- FISHERY: Survey Information, fisheries Calendar, household labour, Fishing Labour, input, output, Gear Rented out, trading
- COMMUNITY: Community Identification, Survey staff Details, Access to basic services, Investments projects, land use, Agriculture, Demography and family issues, Governance, Water and sanitation, Roster of Community leaders, Market price
Topics
| Topic | Vocabulary |
|---|---|
| Food (production, crisis) | FAO |
| Agriculture & Rural Development | FAO |
| Health | FAO |
| Nutrition | FAO |
| Community Driven Development | FAO |
| Access to Finance | FAO |
Coverage
Geographic Coverage
National
Producers and sponsors
Primary investigators
| Name | Affiliation |
|---|---|
| National Bureau of Statistics | Ministry of Finance, Tanzania |
Producers
| Name | Affiliation | Role |
|---|---|---|
| Ministry of Agriculture, Food Security and Cooperatives | Line Ministries | [Technical assistance -] survey design and implementation |
| Ministry of Finance | Line Ministries | [Technical assistance -] survey design and implementation |
| Millennium Challenge Account - Tanzania | Line Ministries | [Technical assistance -] survey design and implementation |
| World Bank | Line Ministries | [Technical assistance -] survey design and implementation |
| Department for International Development | Technical assistance | |
| United Nation Children's Funds | Technical assistance | |
| United Nation Population Funds | Technical assistance | |
| Japan International Cooperation Agency | Technical assistance |
Funding Agency/Sponsor
| Name | Abbreviation | Role |
|---|---|---|
| The European Commission | EU_Commission | Grant provider |
| The World Bank (Living Standards Measurement Study - Integrated Surveys on Agriculture) | WB_LSMS-ISA | Supplementary grant provider |
Sampling
Sampling Procedure
The sample design for the second round of the NPS revisits all the households interviewed in the first round of the panel, as well as tracking adult split-off household members. The original sample size of 3,265 households was designed to representative at the national, urban/rural, and major agro-ecological zones. The total sample size was 3,265 households in 409 Enumeration Areas (2,063 households in rural areas and 1,202 urban areas). It is also be possible in the final analysis to produce disaggregated poverty rates for 4 different strata: Dar es Salaam, other urban areas on mainland Tanzania, rural mainland Tanzania, and Zanzibar.
Since the NPS is a panel survey, the second round of the fieldwork revisits all households originally interviewed during round one. If a household has moved from its original location, the members were interviewed in their new location. If that location was within one hour of the original location, the field team did the interview at the time of their visit to the enumeration area. If the household had located more than an hour from the original location, details of the new location were recorded on specialized forms, and the information passed to a dedicated tracking team for follow-up.
If a member of the original household had split from their original location to form or join a new household, information was recorded on the current whereabouts of this member. All adult former household members (those over the age of 15) were tracked to their new location. Similar to the protocol for the re-located households, if the new household is within one hour of the original location, the new household was interviewed by the main field team at the time of the visit to the enumeration area. For those that have moved more than one hour away, their information was passed to the dedicated tracking team for follow-up. Once the tracking targets have been found, teams are required to interview them and any new members of the household.
The total sample size for the second round of the NPS has a total sample size of 3924 households. This represents 3168 round-one households, a re-interview rate of over 97 percent. In addition, of the 10,420 eligible adults (over age 15 in 2010), 9,338 were re-interviewed, a re-interview rate of approximately 90 percent.
Since the NPS is a panel survey, the second round of the fieldwork revisits all households originally interviewed during round one. If a household has moved from its original location, the members were interviewed in their new location. If that location was within one hour of the original location, the field team did the interview at the time of their visit to the enumeration area. If the household had located more than an hour from the original location, details of the new location were recorded on specialized forms, and the information passed to a dedicated tracking team for follow-up.
If a member of the original household had split from their original location to form or join a new household, information was recorded on the current whereabouts of this member. All adult former household members (those over the age of 15) were tracked to their new location. Similar to the protocol for the re-located households, if the new household is within one hour of the original location, the new household was interviewed by the main field team at the time of the visit to the enumeration area. For those that have moved more than one hour away, their information was passed to the dedicated tracking team for follow-up. Once the tracking targets have been found, teams are required to interview them and any new members of the household.
The total sample size for the second round of the NPS has a total sample size of 3924 households. This represents 3168 round-one households, a re-interview rate of over 97 percent. In addition, of the 10,420 eligible adults (over age 15 in 2010), 9,338 were re-interviewed, a re-interview rate of approximately 90 percent.
Deviations from the Sample Design
The total sample size for the second round of the NPS has a total sample size of 3924 households. This represents 3168 round one household, a re-interview rate of over 97 percent. In addition, of the 10,420 eligible adults (over age 15 in 2010), 9,338 were re-interviewed, a re-interview rate of approximately 90 percent. To obtain the attrition adjustment factor the probability that a sample household was successfully re-interviewed in the second round of surveys is modelled with the linear logistic model at the level of the individual. A binary response variable is created by coding the response disposition for eligible households that do not respond in the second round as 0, and households that do respond as 1.
Response Rate
Approximately 95 percent
Weighting
The weights are developed following these steps:
1) Begin with the “base weights” or those calculated during the first round of the survey; The panel weight calculations are based on the 2008/2009 household weights. These weights are based on the inverse probability of selection, EA level non-response correction, trimming of outlier weights, and a post-stratification correction11. These probability weights form the first component of the 2010-2011 calculations.
W1=W2008
2) Incorporate fair-share weights for composition changes;
Based on the tracking protocols, the tracking for split off rules for the Tanzania NPS allow for the incorporation of people who now live with original sample members. For example, a young adult living with his parents in 2008, may be 2010 have formed a new household, getting married and having a child. The wife and infant will be incorporated into the survey and thus require a probability of selection. Such corrections are routinely used to distribute weight to new sample members in panel surveys.
3) derive attrition adjusted weights for all individuals, including split-off10 households, then aggregate these weights to the household level; All household panel surveys must tackle the problem of attrition, sample members selected for follow interview which cannot be located and/or interviewed.
4) post-stratify the pooled weights to known population totals.
1) Begin with the “base weights” or those calculated during the first round of the survey; The panel weight calculations are based on the 2008/2009 household weights. These weights are based on the inverse probability of selection, EA level non-response correction, trimming of outlier weights, and a post-stratification correction11. These probability weights form the first component of the 2010-2011 calculations.
W1=W2008
2) Incorporate fair-share weights for composition changes;
Based on the tracking protocols, the tracking for split off rules for the Tanzania NPS allow for the incorporation of people who now live with original sample members. For example, a young adult living with his parents in 2008, may be 2010 have formed a new household, getting married and having a child. The wife and infant will be incorporated into the survey and thus require a probability of selection. Such corrections are routinely used to distribute weight to new sample members in panel surveys.
3) derive attrition adjusted weights for all individuals, including split-off10 households, then aggregate these weights to the household level; All household panel surveys must tackle the problem of attrition, sample members selected for follow interview which cannot be located and/or interviewed.
4) post-stratify the pooled weights to known population totals.
Data Collection
Dates of Data Collection
| Start | End |
|---|---|
| 2010-10 | 2011-09 |
Data Collection Mode
Face-to-face [f2f]
Data Processing
Data Editing
CSPro-based data entry/editing system was used. A cross comparison between the entered values in the field based data entry and double entry was conducted and any differences in values between the two were flagged for manual inspection of the physical questionnaire. Corrections based on this inspection exercise were ultimately encoded in the dataset.
Additionally, an extensive review of data files was conducted, including interviewer errors such as missing values, ranges and outliers. Observations were returned for manual inspection of the physical questionnaires if continuous values fell outside five standard deviations of the mean, categorical values were not eligible responses, or there were internal inconsistencies within the dataset (for example, the age of an individual was not consistent with their educational status, there was more than one head of household listed, an individual was engaged in multiple primary activities, the quantity of crops and their by-products produced, harvested, and sold not listed, the distance from the market and an individual's plot was not listed, the number of weeks, days per week, and hours per day an individual engaged in fishery activity was not recorded, the species and quantity of fish caught, bought, sold, or traded was not listed, etc). When it was determined that these values were the result of data-entry error, the values were corrected. In addition, cases deemed to reflect obvious enumerator error were also corrected in this cleaning process. The majority of such cases involved the use of incorrect measurement units, e.g. recording grams as kilograms or vice versa.
Additionally, an extensive review of data files was conducted, including interviewer errors such as missing values, ranges and outliers. Observations were returned for manual inspection of the physical questionnaires if continuous values fell outside five standard deviations of the mean, categorical values were not eligible responses, or there were internal inconsistencies within the dataset (for example, the age of an individual was not consistent with their educational status, there was more than one head of household listed, an individual was engaged in multiple primary activities, the quantity of crops and their by-products produced, harvested, and sold not listed, the distance from the market and an individual's plot was not listed, the number of weeks, days per week, and hours per day an individual engaged in fishery activity was not recorded, the species and quantity of fish caught, bought, sold, or traded was not listed, etc). When it was determined that these values were the result of data-entry error, the values were corrected. In addition, cases deemed to reflect obvious enumerator error were also corrected in this cleaning process. The majority of such cases involved the use of incorrect measurement units, e.g. recording grams as kilograms or vice versa.
Other Processing
To maintain the confidentiality of our respondents, certain parts of the Tanzania NPS database have not been made publicly available. The confidential variables pertain to (i) names of the respondents to the household and community questionnaires, (ii) village and constituency names, (iii) descriptions of household dwelling and agricultural plot locations, (iv) phone numbers of household members and their reference contacts, (v) GPS-based household and agricultural plot locations, (vi) names of the children of the head/spouse living elsewhere, (vii) names of the deceased household members, (viii) names of individuals listed in the network roster, and (ix) names of field staff.
Data Appraisal
Estimates of Sampling Error
To reduce the overall standard errors, and weight the population totals up to the known population figures, a post-stratification correction is applied. Based on the projected number of households in the urban and rural segments of each region, adjustment factors are calculated. This correction also reduces overall standard errors.
Data Appraisal
The estimated logistic model is used to obtain a predicted probability of response for each household member in the 2010/2011 survey. These response probabilities were then aggregated to the household level (by calculating the mean), the using the household-level predicted response probabilities as the ranking variable, all households are ranked into 10 equal groups (deciles). An attrition adjustment factor was then defined as the reciprocal of the empirical response rate for the household-level propensity
Then a logistic response propensity model is fitted, using 2005 UNHS household and individual characteristics measured in the first wave as covariates. In a few limited cases, values of unit level variables were missing from the 2008/2009 household dataset. These values were imputed using multivariate regression and logistic regression techniques. Imputations are done using the 'impute' command in Stata at the level of the UNPS strata (urban/rural and region). Overall, less than one percent of the variables required imputation to replace missing values.
Then a logistic response propensity model is fitted, using 2005 UNHS household and individual characteristics measured in the first wave as covariates. In a few limited cases, values of unit level variables were missing from the 2008/2009 household dataset. These values were imputed using multivariate regression and logistic regression techniques. Imputations are done using the 'impute' command in Stata at the level of the UNPS strata (urban/rural and region). Overall, less than one percent of the variables required imputation to replace missing values.
Access policy
Contacts
| Name | Affiliation | URL | |
|---|---|---|---|
| Director General | [email protected] | http://nbs.go.tz/index.php?option=com_contact&view=contact&id=1&Itemid=69 | |
| Living Standards Measurement Study | World Bank | [email protected] | www.worldbank.org/lsms |
Confidentiality
https://microdata.worldbank.org/index.php/terms-of-use
Access conditions
The dataset has been anonymized and is available as a Public Use Dataset. It is accessible to all for statistical and research purposes only, under the following terms and conditions:
1. The data and other materials will not be redistributed or sold to other individuals, institutions, or organizations without the written agreement of the Nationa Bureau of Statistics, Tanzania.
2. The data will be used for statistical and scientific research purposes only. They will be used solely for reporting of aggregated information, and not for investigation of specific individuals or organizations.
3. No attempt will be made to re-identify respondents, and no use will be made of the identity of any person or establishment discovered inadvertently. Any such discovery would immediately be reported to the National Bureau of Statistics.
4. No attempt will be made to produce links among datasets provided by the NBS, or among data from the National Bureau of Statistics and other datasets that could identify individuals or organizations.
5. Any books, articles, conference papers, theses, dissertations, reports, or other publications that employ data obtained from the National Bureau of Statistics will cite the source of data in accordance with the Citation Requirement provided with each dataset.
6. An electronic copy of all reports and publications based on the requested data will be sent to the National Bureau of Statistics
The original collector of the data, the National Bureau of Statistics, and the relevant funding agencies bear no responsibility for use of the data or for interpretations or inferences based upon such uses.
1. The data and other materials will not be redistributed or sold to other individuals, institutions, or organizations without the written agreement of the Nationa Bureau of Statistics, Tanzania.
2. The data will be used for statistical and scientific research purposes only. They will be used solely for reporting of aggregated information, and not for investigation of specific individuals or organizations.
3. No attempt will be made to re-identify respondents, and no use will be made of the identity of any person or establishment discovered inadvertently. Any such discovery would immediately be reported to the National Bureau of Statistics.
4. No attempt will be made to produce links among datasets provided by the NBS, or among data from the National Bureau of Statistics and other datasets that could identify individuals or organizations.
5. Any books, articles, conference papers, theses, dissertations, reports, or other publications that employ data obtained from the National Bureau of Statistics will cite the source of data in accordance with the Citation Requirement provided with each dataset.
6. An electronic copy of all reports and publications based on the requested data will be sent to the National Bureau of Statistics
The original collector of the data, the National Bureau of Statistics, and the relevant funding agencies bear no responsibility for use of the data or for interpretations or inferences based upon such uses.
Citation requirements
National Bureau of Statistics (NBS) [Tanzania]. 2011. Tanzania National Panel Survey Report (NPS) - Wave 2, 2010 - 2011. Dar es Salaam, Tanzania: NBS. (www.nbs.go.tz)
Disclaimer and copyrights
Disclaimer
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
Metadata production
DDI Document ID
DDI_TZA_2010-2011_NPS-W2_v01_EN_M_v01_A_OCS_FAO
Producers
| Name | Abbreviation | Affiliation | Role |
|---|---|---|---|
| Office of Chief Statistician | OCS | Food and Agriculture Organization | Adoption of DDI for FAM |
| National Bureau of Statistics | NBS | Survey Implementer |
DDI Document version
TZA_2010-2011_NPS-W2_v01_EN_M_v01_A_OCS_v01