2 resultados para Continuous functions
em DRUM (Digital Repository at the University of Maryland)
Resumo:
Causal inference with a continuous treatment is a relatively under-explored problem. In this dissertation, we adopt the potential outcomes framework. Potential outcomes are responses that would be seen for a unit under all possible treatments. In an observational study where the treatment is continuous, the potential outcomes are an uncountably infinite set indexed by treatment dose. We parameterize this unobservable set as a linear combination of a finite number of basis functions whose coefficients vary across units. This leads to new techniques for estimating the population average dose-response function (ADRF). Some techniques require a model for the treatment assignment given covariates, some require a model for predicting the potential outcomes from covariates, and some require both. We develop these techniques using a framework of estimating functions, compare them to existing methods for continuous treatments, and simulate their performance in a population where the ADRF is linear and the models for the treatment and/or outcomes may be misspecified. We also extend the comparisons to a data set of lottery winners in Massachusetts. Next, we describe the methods and functions in the R package causaldrf using data from the National Medical Expenditure Survey (NMES) and Infant Health and Development Program (IHDP) as examples. Additionally, we analyze the National Growth and Health Study (NGHS) data set and deal with the issue of missing data. Lastly, we discuss future research goals and possible extensions.
Resumo:
Distant Light: Songs on Texts by Richard Boada is a collection of songs for baritone voice, piano, alto saxophone, and percussion (vibraphone and marimba). The texts do not present a continuous narrative, but they share common themes. Most are set in the rural South and deal with the conflict between nature and industrial development. This piece functions as a cohesive whole, but each song could be performed separately and would be effective out of the context of the entire work. Distant Light is made up of eight songs and is approximately 23 minutes in duration.