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This research study aims to examine how family size affects the educational attainment and work participation of children in Mexico. The quantity-quality model suggests that larger families may reduce investment in education. The study uses instrumental variables, such as twin births and same-sex siblings, to identify the causal effect. The analysis is based on a large sample of households and children aged 11-17 from the Mexican ENCASEH survey. The results will contribute to the existing literature on the effects of family size on education in developing countries.
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How family size affects children’s schooling and work in Mexico Emla Fitzsimons Bansi Malde 27 Feb 08
Introduction • Question of Interest • Does family size affect children’s school and/or work participation? • Theory • Quantity-Quality model: bigger families (quantity) reduce investment in schooling (quality) • Empirical Issues • To test how well the quantity-quality model fits reality requires exogenous changes in fertility that are uncorrelated with preferences or budget constraints • We use Instrumental Variables to identify the causal effect
Instrumental Variables We use the following instruments • Twin births: increases family size by definition • First n children are of the same sex: increases family size if parents have preferences for having children of both sexes • Note, the literature that considers the causal effects of family size basically always uses these instruments
A glance at the literature! • Most of these studies consider developed countries and outcomes different to ours (female labour supply) • Literature most comparable to what we do (effects of family size on education in developing countries): • India: Rosenzweig & Wolpin (1980) • China: Qian (2006), Rosenzweig & Zhang (2006) • Korea: Lee (2004) • Brazil: Ponczek & Souza (2007) • Colombia: Baez (2007) • We will hopefully improve on them thanks to extremely large samples
Methodology • Basic model • IV first stage • Using same-sex instrument • Using twins instrument
Data • The main source we use is the Mexican ENCASEH survey: cross-sectional census data collected across marginalised rural areas b/w 1996 and 1999 • Info on individual, household and locality characteristics • Restrict sample to children aged 11-17 • Drop households with • both parents not living together/not married • eldest child>18 • >1 household head So we’re left with a sample of ~600,000 households and ~1.1million children aged 11-17 • Note, average # of children per family in our sample is 4.3 • We’re also going to merge these data with the PROGRESA surveys, as there’s v useful info for our purposes in these - we’ll come back to this later
Issues/Next Steps Validity of Instruments Economies of scale? (Rosenzweig and Wolpin (2000))
Issues/Next Steps Robustness Checks • Compare results across different instruments (what we have just shown) • Use an instrument that should suffer much less from this issue: twins at second birth that are of different sex from first-born sensitivity first stage.doc; sensitivity second stage.doc • Use PROGRESA consumption data to see if there is any evidence of economies of scale • we observe expenditure on children’s clothes and shoes, separately by sex: we are going to use these data to see if sex-sameness affects these expenditures • we also observe value of assets, may be useful • Assess sensitivity of parameter estimates to different correlations b/w the IV and the error term using method of Ashley (2008); (note refine correlations using info from PROGRESA data)
Issues/Next Steps • Results obtained from the IV are all LATE and affect only particular types of households • How do we reconcile all these different LATEs?