The National Income Dynamics Study (NIDS) is a face-to-face longitudinal survey of individuals living in South Africa as well as their households. The survey was designed to give effect to the dimensions of the well-being of South Africans, to be tracked over time. At the broadest level, these were:
Wealth creation in terms of income and expenditure dynamics and asset endowments;
Demographic dynamics as these relate to household composition and migration;
Social heritage, including education and employment dynamics, the impact of life events (including positive and negative shocks), social capital and intergenerational developments;
Access to cash transfers and social services
Wave 1 of the panel survey, conducted in 2008, collected the detailed information for the national sample.
Waves 2 to 4 of the panel survey re-interviewed respondents interviewed in previous waves, gathering information on developments in their lives over the years.
Completed and non-response interviews in the NIDS data:
The NIDS datasets contain both completed and non-response interviews (e.g. Refusals). It is recommended that researchers limit their research to completed interviews to avoid item non-response from non-response interviews. The completed interviews can be identified by making use of the w`x'_`y'_outcome variables, where `x' represents the wave and `y' represents the relevant data file/outcome type indicator. These outcome variables can be found in each of the following data files, Adult, Child, Proxy, HHQuestionnaire and Link File.
The only exception to this is Wave 1 where no outcome variable exists. This is because at a household level, all of the interviews are completed. However this does not apply at an individual level where non-response interviews can be identified by making use of the "Reason for refusal" variables, namely w1_a_refexpl or w1_c_refexpl in the Adult and Child data files respectively.
Kind of Data
Sample survey data [ssd]
Unit of Analysis
Households and individuals
v2.0.0: Edited, anonymised dataset for public distribution.
This explains changes in any new versions of the data. Note that the version numbers for the latest versions of NIDS have not been updated in the do files in the program library that has been made available to assist researchers with data manipulation. Data users should update the global to the version of the data they are using.
Version 1 of the National Income Dynamics Study wave 4 2014-2015 public release dataset was produced on the 12th of May 2016
CHANGES IN VERSION 1.1
Changes from Panel weights and post-stratified weights:
Changes were made to the weight variables, w4_pweight in the indderived data file and the w4_wgt in the hhderived data file. Changes in these variables were caused by:
Missing panel weights for some babies born to CSM mothers after Wave 1 (2008).
One (now adult) respondent with a missing weight.
The following CSM/ TSM changes were made to the data.
PID 721857 - Is a TSM who was incorrectly reflected as a CSM.
PID 682522 - This child was previously not recorded as being resident in any household. Her record has now been corrected to reflect that she is a resident in the household in which she shares with her mother.
PID 617044 - This individual was interviewed under pid 622914. Pid 617044 has now been removed as it is a duplicate of pid 622914.
To correct a data error an update was made to 13 questionnaires to update their month of interview from September 2014 to October 2014.
CHANGES IN VERSION 2.0.0
Version 2.0.0 of NIDS wave 4 includes changes to the number of individuals and households in each data file, largely driven by previously incorrect classification of TSM/CSM status, duplicate interviews and additional baby CSMs not captured in a previous version of this wave. Version 2.0.0 also contains new and renamed variables, and there are changes to the survey weights. For details on these changes please see the document Wave 4 Changes between V1.1 and V2.0.0 which is provided with the data.
Data on the following topics was collected during the panel survey:
HOUSEHOLD: Household characteristics, household roster, mortality history, living standards, expenditure, consumption, negative events, positive events, agriculture
ADULTS: Demographics, education, labour market participation, income, health, well-being, numeracy, anthropometric data
CHILDREN: Education, health, family support, grants, anthropometric data, numeracy
The NIDS data is nationally representative. The survey began in 2008 with a nationally representative sample of over 28,000 individuals in 7,300 households across the country. The survey is repeated every two years with these same household members, who are called Continuing Sample Members (CSMs). The survey is designed to follow people who are CSMs, wherever they may be in SA at the time of interview. The NIDS data is therefore, by design, not representative provincially or at a lower level of geography (e.g. District Council).
The lowest level of geographic aggregation in the NIDS public release data is District Municipality. However, the data is not representative at any level but the national level. Data that includes household-level geo-coding is available for use in DataFirst's Secure Centre at the University of Cape Town.
The target population for NIDS was private households in all nine provinces of South Africa, and residents in workers' hostels, convents and monasteries. The frame excludes other collective living quarters, such as student hostels, old age homes, hospitals, prisons and military barracks.
Producers and sponsors
Southern Africa Labour and Development Research Unit
Registering to use the NIDS data includes an agreement that the data user will not attempt to identify specific individuals from the data.
Public use data, available to all
Southern Africa Labour and Development Research Unit. National Income Dynamics Study 2014-2015, Wave 4 [dataset]. Version 2.0.0. Pretoria: Department of Planning, Monitoring, and Evaluation, SA Presidency [funding agency]. Cape Town: Southern Africa Labour and Development Research Unit [implementer], 2016. Cape Town: DataFirst [distributor], 2016. DOI: https://doi.org/10.25828/f4ws-8a78