Estimating expenditure impacts without expenditure data using asset proxies

When asset indices are used in regressions the coefficients obtained are typically difficult to interpret. We show how lower bounds on expenditure effects can be extracted, if the relationship between the assets and expenditure can be calibrated on an auxiliary data set.asset index, proxy variables, attenuation, obesity

Dissecting post-apartheid labour market developments: Decomposing a discrete choice model while dealing with unobservables

The abolition of apartheid should have improved the employment prospects of black South Africans. The reality seems to have been different, with rising unemployment rates. Disentangling the real trends from changes in measurement and sampling design has proved to be difficult. We tackle this issue by means of an new methodology for decomposing changes in a proportion. Our approach is based on a methodology presented by Lemieux for continuous variables. In particular we show how we can construct counterfactual data at the individual level controlling for unobservable effects. We show that this methodology has many attractive features when compared to other approaches available. In particular it lends itself to graphical analyses. We use this methodology to explore changes in the proportion of African men being employed, unemployed and not economically active in South Africa in the post-apartheid period. Our results suggest that changes in the characteristics of these men have made them more employable over time, but that the propensity to be employed has declined. One might say that the human and social capital of these men has improved, but that the returns on that capital have declined. The net effect has been to leave measured employment more or less static. Changes in their characteristics and in their propensity to be economically active have both worked towards increasing the participation rate. As a consequence unemployment has risen over time. The analysis confirms that there are important measurement changes between different national surveys.decomposition, discrete choice models, South Africa, employment, unemployment, participation

Lazy Rotten Sons? Relatedness, gender and the intra-household allocation of work and leisure in South Africa

We investigate the balance between work (including home production), leisure and personal care (chiefly sleep) within South African households. We use the South African time use survey which enables us to obtain a better measure of the division of total labour (paid and unpaid) within South African households than previous studies have been able to. Furthermore we construct a measure of "genetic" relatedness between the respondent and other members of the household. We find that women that are more closely related to other household members do more work and enjoy less leisure than more peripheral individuals. Single men, by contrast, seem to do less work and enjoy more leisure if they are more closely related to other household members. Our findings are not compatible with the unitary model of the household. They suggest that men extract extra leisure because of the anticipated altruism shown by women.altruism, genetic relatedness, Hamilton’s rule, intra-household allocation, rotten kid theorem, time use

Nonparametric estimation when income is reported in bands and at points

We show how to estimate kernel density functions of distributions in which some of the responses are provided in brackets, by inverse probability weighting. We consider two cases, one where the data are CAR and where the data are not CAR. We show how the selection probabilities can be estimated by means of the EM algorithm without specifying a parametric distribution function for the variable. A Monte Carlo experiment shows that this procedure estimates the selection parameters fairly precisely. We apply these techniques to earnings data from South Africa’s first post-apartheid nationally representative survey, the 1994 October Household Survey.coarsening, bracket responses, EM algorithm, inverse probability weighting

The mystery of South Africa's ghost workers in 1996: measurement and mismeasurement in the manufacturing census, population census and October Household Surveys

This paper compares estimates of total manufacturing employment from South Africa's 1996 manufacturing census, the 1996 population census and the October Household Surveys from 1995, 1996 and 1997. Findings show that there are 300 000 too few manufacturing workers recorded in the 1996 population census. Furthermore there are other inconsistencies between these data sources. Several possible explanations for the deficit in manufacturing workers are put forward, but none are compelling. It is concluded that aggregate employment series constructed from household surveys should be treated with caution.

Sample Survey Calibration: An Informationtheoretic perspective

We show that the pseudo empirical maximum likelihood estimator can be recast as a calibration estimator. The process of estimating the probabilities pk of the distribution function can be done also in a maximum entropy framework. We suggest that a minimum cross-entropy estimator has attractive theoretical properties. A Monte Carlo simulation suggests that this estimator outperforms the PEMLE and the Horvitz-Thompson estimator. This is a joint SALDRU/DataFirst Working Paper as part of the Mellon Data Quality Project. For more information about the project visit www.datafirst.uct.ac.za.sample weights, calibration, pseudo-empirical maximum likelihood estimation, cross entropy

Restructuring of Households in Rural South Africa: Reflections on Average Household Size in the Agincourt Sub-district 1992-2003

South Africa has seen a dramatic decrease in household size over the last decade. In Table 1 we show that over the eight-and-a-half years from October 1995 to March 2004 the average household size has decreased by 20% or 0.74 persons (see also Pirouz 2004). Consequently for a fixed population size there would have been 20% more households in March 2004 than in October 1995. Such a rapid rate of household formation is interesting in and of itself. From the perspective of a policy maker it is particularly vital to understand this process. The new democratic government has committed itself to extending infrastructure and social services to households in deprived communities and now finds that it is trying to catch a moving target. The backlogs are increasing as the services are being rolled out. We will suggest below that there might be a connection between these two processes.

Re-weighting South African National Household Survey Data to create a consistent series over time: A cross entropy estimation approach

In the absence of established longitudinal panel surveys in South African, national cross-sectional household survey data are frequently used to analyse change. When these data are stacked side-byside, however, inconsistencies both in time trends and between household and person level data are found. This study uses a new set of weights calibrated to the ASSA 2003 model totals using a cross entropy estimation approach. This approach is favoured because the calculated weights are similar to the initial sample weights (and hence retain the survey design benefits) but match to a series of age-sex-race and province marginal totals that are consistent over time. The weights are publicly available for a fourteen year period between 1994 and 2007. This is a SALDRU/DataFirst Working Paper

Errors in the October household survey 1994 available from the South African Data Archive

The on-line electronic documentation supplied with the 1994 October Household Survey by the South African Data Archive (SADA) appears to be incorrect. In particular, the electronic version of the questionnaire does not correspond to the hard copy in the possession of the author. The most serious error is that the race classification in the electronic copy is different from the classification on the hard copy. Researchers relying on the electronic copy will erroneously interchange the categories “Coloured”, “White” and “Black”. This could lead to seriously misleading analyses. The reason for this mistake can probably be attributed to a retyping of the questionnaire using the 1993 OHS as a template

Weighing the value of Asset Proxies: The case of the Body Mass Index in South Africa

There are many household surveys, e.g. the Demographic and Health Surveys, that carry a wealth of useful information but in which information of interest to economists, chiefly or missing altogether. In many of these surveys, however, there are questions about asset ownership. These might be used to proxy for income. Indeed some authors have suggested that asset-based measures of wellbeing may even be better than income or expenditure-based ones, since they may reflect of the household better. They may also be more accurately measured (Filmer and Pritchett 2001, Sahn and Stifel 2003). This is a joint SALDRU/DataFirst Working paper as part of the Mellon Data Quality Project. For more information about the project visit www.datafirst.uct.ac.za.