William M. Mason

Contextually Specific Effects and other Generalizations of the Hierarchical Linear Model for Comparative Analysis

Abstract Contextually specific differences among members of a context pose substantive and methodological problems in multilevel analysis. An important example is ethnic identity in comparative studies involving different societies. Ethnic (and religious) group membership in many societies is a basis not only for differentiation among members but also for the identification and maintenance of deeply rooted integrative ties. So important is ethnicity that the existence of different groups within societies sometimes delays or prohibits the taking of censuses. Moreover, even when ethnic information is available in national statistical data sources, researchers are sometimes prohibited from reporting the results of analyses that contain ethnic detail. Despite these constraints, information on ethnicity is often available for pluralistic societies. Where it is available, ethnicity poses a challenging analytic problem for comparative analysis. If researchers wish to compare different societies, how is ethnicity...

A cautionary case study of approaches to the treatment of missing data

This article presents findings from a case study of different approaches to the treatment of missing data. Simulations based on data from the Los Angeles Mammography Promotion in Churches Program (LAMP) led the authors to the following cautionary conclusions about the treatment of missing data: (1) Automated selection of the imputation model in the use of full Bayesian multiple imputation can lead to unexpected bias in coefficients of substantive models. (2) Under conditions that occur in actual data, casewise deletion can perform less well than we were led to expect by the existing literature. (3) Relatively unsophisticated imputations, such as mean imputation and conditional mean imputation, performed better than the technical literature led us to expect. (4) To underscore points (1), (2), and (3), the article concludes that imputation models are substantive models, and require the same caution with respect to specificity and calculability.

What Can We Learn About Effective Early Mathematics Teaching? A Framework for Estimating Causal Effects Using Longitudinal Survey Data

Abstract This study investigates the impact of teacher characteristics and instructional strategies on the mathematics achievement of students in kindergarten and first grade and tackles the question of how best to use longitudinal survey data to elicit causal inference in the face of potential threats to validity due to nonrandom assignment to treatment. We develop a step-by-step approach to selecting a modeling and estimation strategy and find that teacher certification and courses in methods of teaching mathematics have a slightly negative effect on student achievement in kindergarten, whereas postgraduate education has a positive effect in first grade. Various teaching modalities, such as working with counting manipulatives, using math worksheets, and completing problems on the chalkboard, have positive effects on achievement in kindergarten, and pedagogical practices relating to explaining problem solving and working on problems from textbooks have positive effects on achievement in first grade. We show that the conclusions drawn depend on the estimation and modeling choices made and that several prior studies of teacher effects using longitudinal survey data likely neglected important features needed to establish causal inference.

Prenatal Sex-Selective Abortion and High Sex Ratio at Birth in the Rural Henan Province

Based on data from a snowball sampling survey conducted in rural Henan in 2001, we analyze the prevalence, patterns, and risk factors of prenatal sex selection and estimate its impact on sex ratio at birth. Our results indicate that prenatal sex selection is widely known and practiced in rural Henan; ex ante fetal sex and family sibset composition are the dominant predictors of abortion, regardless of maternal heterogeneity; and sex-selective abortion is the predominant, if not sole, cause of the samples high sex ratio at birth.