The external validity of treatment effects: an investigation of educational production

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dc.contributor.advisorWittenberg, Martinen_ZA
dc.contributor.authorMuller, Sean Mfundzaen_ZA
dc.date.accessioned2015-07-03T08:26:53Z
dc.date.available2015-07-03T08:26:53Z
dc.date.issued2014en_ZA
dc.descriptionIncludes bibliographical references.en_ZA
dc.description.abstractThe thesis begins, in chapter 1, with an overview of recent debates concerning the merits of randomised programme evaluations and a detailed review of the literature on the extrapolation of treatment effects ('external validity'). Building on the insights of Cook and Campbell (1979) and a result by Hotz, Imbens, and Mortimer (2005), I then argue that the fundamental challenge to external validity may be interactive relationships between the treatment variable and other covariates. The empirical relevance of this claim is developed through two contributions to the economics of education literature, using data from the Tennessee class size experiment known as 'Project STAR'. Chapter 2 contributes to the literature on teacher quality, describing and implementing a novel method for constructing a value-added quality measure that uses a single cross-section of data in which students and teachers are randomly assigned to different-sized classes. The core insight is that constructing the value-added measure within treatment categories creates a plausible measure of quality that is simultaneously independent of treatment. The analysis of chapter 3 concerns the literature on class size effects. I argue that the effect of class size on educational achievement may be dependent on other class-level factors and that this should be considered when estimating educational production functions. Using the variable constructed in chapter 2, I estimate interaction effects between class size and teacher quality and find a number of statistically and economically significant effects. Specifically, higher quality teachers are associated with more beneficial effects of smaller classes. Those results suggest a possible unification of the class size and teacher quality literatures, with the policy problem being one of finding an optimal combination of these two factors. The broader contribution, further to the analysis of chapter 1, is to illustrate an obstacle to external validity: class size effects are unlikely to be the same across contexts where the teacher quality distribution differs. The experimental estimation of class size effects therefore serves as an empirical case study of the challenges to external validity that arise from interaction.en_ZA
dc.identifier.apacitationMuller, S. M. (2014). <i>The external validity of treatment effects: an investigation of educational production</i>. (Thesis). University of Cape Town ,Faculty of Commerce ,School of Economics. Retrieved from http://hdl.handle.net/11427/13324en_ZA
dc.identifier.chicagocitationMuller, Sean Mfundza. <i>"The external validity of treatment effects: an investigation of educational production."</i> Thesis., University of Cape Town ,Faculty of Commerce ,School of Economics, 2014. http://hdl.handle.net/11427/13324en_ZA
dc.identifier.citationMuller, S. 2014. The external validity of treatment effects: an investigation of educational production. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Muller, Sean Mfundza AB - The thesis begins, in chapter 1, with an overview of recent debates concerning the merits of randomised programme evaluations and a detailed review of the literature on the extrapolation of treatment effects ('external validity'). Building on the insights of Cook and Campbell (1979) and a result by Hotz, Imbens, and Mortimer (2005), I then argue that the fundamental challenge to external validity may be interactive relationships between the treatment variable and other covariates. The empirical relevance of this claim is developed through two contributions to the economics of education literature, using data from the Tennessee class size experiment known as 'Project STAR'. Chapter 2 contributes to the literature on teacher quality, describing and implementing a novel method for constructing a value-added quality measure that uses a single cross-section of data in which students and teachers are randomly assigned to different-sized classes. The core insight is that constructing the value-added measure within treatment categories creates a plausible measure of quality that is simultaneously independent of treatment. The analysis of chapter 3 concerns the literature on class size effects. I argue that the effect of class size on educational achievement may be dependent on other class-level factors and that this should be considered when estimating educational production functions. Using the variable constructed in chapter 2, I estimate interaction effects between class size and teacher quality and find a number of statistically and economically significant effects. Specifically, higher quality teachers are associated with more beneficial effects of smaller classes. Those results suggest a possible unification of the class size and teacher quality literatures, with the policy problem being one of finding an optimal combination of these two factors. The broader contribution, further to the analysis of chapter 1, is to illustrate an obstacle to external validity: class size effects are unlikely to be the same across contexts where the teacher quality distribution differs. The experimental estimation of class size effects therefore serves as an empirical case study of the challenges to external validity that arise from interaction. DA - 2014 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2014 T1 - The external validity of treatment effects: an investigation of educational production TI - The external validity of treatment effects: an investigation of educational production UR - http://hdl.handle.net/11427/13324 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/13324
dc.identifier.vancouvercitationMuller SM. The external validity of treatment effects: an investigation of educational production. [Thesis]. University of Cape Town ,Faculty of Commerce ,School of Economics, 2014 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/13324en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentSchool of Economicsen_ZA
dc.publisher.facultyFaculty of Commerceen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherEconomicsen_ZA
dc.titleThe external validity of treatment effects: an investigation of educational productionen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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