Sample selection bias and the South African wage function
Stellenbosch Working Paper Series No. WP18/2008Publication date: 2008
Author(s):
Conventional wage analyses suffers from a debilitating ailment: since there are no observable market wages for individuals who do not work, findings are limited to the sample of the population that are employed. Due to the problem of sample selection bias, using this subsample of working individuals to draw conclusions for the entire population will lead to inconsistent estimates. Remedial procedures have been developed to address this issue. Unfortunately, these models strongly rely on the assumed parametric distribution of the unobservable residuals as well as the existence of an exclusion restriction, delivering biased estimates if either of these assumptions is violated. This has given rise to a recent interest in semi-parametric estimation methods that do not make any distributional assumptions and are thus less sensitive to deviations from normality. This paper will investigate a few proposed solutions to the sample selection problem in an attempt to identify the best model of earnings for South African data.
JEL Classification:C14, C15, C34, J21
Keywords:Semiparametric and nonparametric methods; Simulation methods; Truncated and censored models; Labour force and employment, Size, and structure
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Monday 28 July 202512:00-13:00
Dr Neil Rankin: Ceo Of Predictive Insights & Stellenbosch University
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Topic: "Two competing approaches in South African competition policy: merger control and anti-cartel enforcement over the past 30 years"
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Professor Johan Fourie: Stellenbosch University
Topic: "Economic History: TBC"
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18 Jul 2025 Encouraging data, but messy politics while US tariff deadline loomsThe big global data prints of the week came on Tuesday, with better-than-expected Chinese GDP growth for Q2 and US core CPI coming in lower than expected, but still (finally) reflecting some signs of tariffs being passed on to consumers. Locally, the uptick in mining production and retail sales was positive for Q2 GDP dynamics. In addition to the data,...
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