"Likelihood-Based Methods of Mediation Analysis in the Context of Health Disparities" (Next Week at the Statistics Seminar)
Attention conservation notice: Only of interest if you (1) care about evidence on how inequality matters for health, and (2) will be
in Pittsbrugh on Tuesday.
- Therri Usher, "Likelihood-Based Methods of Mediation Analysis in the Context of Health Disparities"
- Abstract: African-Americans experience higher incidences of death
and disability compared to non-Hispanic whites. Much of the existing research
has focused on identifying the existence of health disparities, as
methodological issues have hampered the development of health disparities
research. In order to create solutions to eliminate health disparities,
research must understand the mechanisms powering their existence.
- Existing causal inference tools are not suitable for studying racial health
disparities, as race cannot be manipulated or changed. For the same reason,
mediators stand to be useful in creating avenues to intervene on existing
health disparities. Structural equation modeling (SEM) may be a more promising
tool for quantifying the causal framework of health disparities.
- One of the most widely-used tests for assessing mediation is the Sobel test
(Sobel, 1982; MacKinnon et al, 2007). However, it has disadvantages, including
lower power at smaller sample sizes. Therefore, this work focuses on three
varying methods for assessing mediation and compares their performance to the
- The first method is an adjustment of the Sobel test that utilizes variance
estimation using random covariates. The second method utilizes the joint
distribution of the mediator and the outcome to determine profile likelihoods
for the estimands of interest in order to derive distributions for their
estimates. Finally, the third method utilizes Bayesian modeling techniques to
fit the structural equation models and estimating the probability of mediation
through quantile estimation. Simulations provided evidence that all three
methods demonstrated comparable estimated statistical power compared to the
Sobel test, often showcasing superior power at smaller sample sizes while
providing more tools of inference into the presence of mediation.
- The methods were applied to assess whether diet mediates the relationship
between race and blood pressure in non-Hispanic black and white subjects in the
National Health and Nutrition Examination Survey (NHANES) from 1999-2004.
- Time and place: 4:30--5:30 pm on Tuesday, 23 February 2016,
in Baker Hall A51
As always, the talk is free and open to the public.
Enigmas of Chance;
Constant Conjunction Necessary Connexion
Posted at February 20, 2016 20:46 | permanent link