Daniel F. McCaffrey

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Many statistical methods rely on numerical optimization to estimate a model’s parameters. Unfortunately, conventional algorithms sometimes fail. Even when they do converge, there is no assurance that they have found the global, rather than a local, optimum. We test a new optimization algorithm, simulated annealing, on four econometric problems and compare(More)
Causal effect modeling with naturalistic rather than experimental data is challenging. In observational studies participants in different treatment conditions may also differ on pretreatment characteristics that influence outcomes. Propensity score methods can theoretically eliminate these confounds for all observed covariates, but accurate estimation of(More)
In the past twenty years there has been much interest in the physical and biological sciences in nonlinear dynamical systems that appear to have random, unpredictable behavior. One important parameter of a dynamic system is the dominant Lyapunov exponent (LE). When the behavior of the system is compared for two similar initial conditions, this exponent is(More)
PURPOSE To measure health-related quality of life among adult patients with human immunodeficiency virus (HIV) disease; to compare the health-related quality of life of adults with HIV with that of the general population and with patients with other chronic conditions; and to determine the associations of demographic variables and disease severity with(More)
Outcomes research often requires estimating the impact of a binary treatment on a binary outcome in a non-randomized setting, such as the effect of taking a drug on mortality. The data often come from self-selected samples, leading to a spurious correlation between the treatment and outcome when standard binary dependent variable techniques, like logit or(More)
CONTEXT Studies of selected populations suggest that not all persons infected with human immunodeficiency virus (HIV) receive adequate care. OBJECTIVE To examine variations in the care received by a national sample representative of the adult US population infected with HIV. DESIGN Cohort study that consisted of 3 interviews from January 1996 to January(More)
The use of complex value-added models that attempt to isolate the contributions of teachers or schools to student development is increasing. Several variations on these models are being applied in the research literature, and policy makers have expressed interest in using these models for evaluating teachers and schools. In this article, we present a(More)
Acknowledgments Preface T he concept is simple and attractive: Evaluate teachers on the basis of how much academic growth their students experience over the course of the school year. Often referred to as " value-added, " this concept and the statistical methods for implementing it have been a topic of debate in state legislatures and at state and national(More)
The use of propensity scores to control for pretreatment imbalances on observed variables in non-randomized or observational studies examining the causal effects of treatments or interventions has become widespread over the past decade. For settings with two conditions of interest such as a treatment and a control, inverse probability of treatment weighted(More)