Title:  Methodology:  Report on NIDS Wave 1

Author(s):  Murray Leibbrandt, Ingrid Woolard and Louise de Villiers

Date:  July 2009

In 2006, the South African Presidency embarked on an intensive effort to track changes in the well-being of South Africans by closely following about 28 000 people - young and old, rich and poor - over a period of years. The National Income Dynamics Study (NIDS) will be the first national panel study to document the dynamic structure of a sample of household members in South Africa and changes in their incomes, expenditures, assets, access to services, education, health and other dimensions of well-being. A key feature of the panel study is its ability to follow people as they move out of their original 7 305 households. In doing this, the movement of household members as they leave and/or return to the household or set up their own households will be adequately captured in subsequent waves. The first "baseline" wave of NIDS was conducted by the Southern Africa Labour and Development Research Unit (SALDRU) based at the University of Cape Town’s School of Economics. The first wave of fieldwork commenced in February 2008, with data and report release in July 2009. The design of NIDS envisaged data collection every two years.

Title:  Weights:  Report on NIDS Wave 1

Author(s):  Martin Wittenberg

Date:  July 2009

The NIDS weights were derived in two stages. In the first, the design weights were calculated as the inverse of the inclusion probability. In the second, the weights were calibrated to the 2008 midyear estimates. In practice the process was a bit more complicated so there are not just two sets of weights available. In this document we set out how the weights were calculated and what choices were necessary in the process.

Title:  Household Income:  Report on NIDS Wave 1

Author(s):  Jonathan Argent

Date:  July 2009

This report gives a brief overview of the income data from the National Income Dynamics Study (NIDS). The derivation of household income measures is addressed first, followed by a discussion of the data quality issues encountered. Non-response emerges as the most significant problem. This is not surprisingly, given that high non-response is a phenomenon consistent across previous household surveys in South Africa that involve income measurement. The treatment of the non-response for the purpose of estimating household income is explained and it’s impact is assessed. Discussion of the sample design, household non-response and the weights used to correct for both of these is beyond the scope of this report. A table listing the household and individual level income variables as they appear in the data and the do-files can be found in the appendix.

Title:  Expenditure:  Report on NIDS Wave 1

Author(s):  Arden Finn, Simon Franklin, Malcolm Keswell, Murray Leibbrandt and Jim Levinsohn

Date:  July 2009

This report describes the construction of an aggregate household expenditure variable for the 2008 National Income Dynamics Survey (NIDS.) Section 2 discusses the construction of the food and non-food aggregate expenditure variables. Section 3 explains the construction of the housing expenditure variable. Each of these sections briefly discusses the questionnaire design, the patterns of non-response in the data, and the methods used to impute missing values. In section 4, we compare our constructed aggregate expenditure with the reported aggregate expenditure. In section 5, we conduct some basic analyses using the derived total expenditure variable. We examine the components of household expenditure. We also analyze differences in expenditures by key descriptors such as race and geotype. The analysis concludes by comparing the derived total expenditure variable to the derived total income variable.

Title: A comment on the use of “cluster” corrections in the context of panel data

Author(s):  Martin Wittenberg

Date:  August 2013

Many researchers have asked what “cluster” correction would be appropriate for the second (or subsequent) waves of the NIDS panel. This is not a straightforward issue and requires some clarity as to what the correction is designed to achieve.

Title: Validation of the 10-item Centre for Epidemiological Studies Depression Scale (CES-D-10) in Zulu, Xhosa and Afrikaans populations in South Africa

Author(s): Emily Claire Baron1, Thandi Davies and Crick Lund

Date: January 2017

In 2016 the NIDS team commissioned this paper to look at the validity of the CES-D-10 mental health module used in the NIDS Adult questionnaires. The 10-item Centre for Epidemiological Studies Depression Scale (CES-D-10) is a depression screening tool that had not been validated in South Africa. This study aimed to establish the reliability and validity of the CES-D-10 in Zulu, Xhosa and Afrikaans. The CES-D-10s psychometric properties were also compared to the Patient Health Questionnaire (PHQ-9), a depression screening tool already validated in South Africa. The conclusion is that The CES-D-10 is a valid, reliable screening tool for depression in Zulu, Xhosa and coloured Afrikaans populations.