Convex States

What is a convex set?  An object is convex if for every pair of points within the object, every point on the straight line segment that joins them is also within the object.  Mathematically, we can define a convex set as follows. C is a convex set if: αx+(1-α)y ∈ C, ∀ α ∈ [0,1], ∀ x,y ∈ C. In other words, this…

Why have disability rates decreased?

“Although the evidence was mixed for the 1980s and it is difficult to pinpoint when in the 1990s the decline began, during the mid- and late 1990s, the panel found consistent declines on the order of  0-2.5% per year for two commonly used measures in the disability literature: difficulty with daily activities and help with…

Adaptive Partial Drug Approval

Currently the FDA requires that drug companies conduct 3 phases in order to secure the approval of a pharmaceutical. These are: Phase I. These are smaller (20-80 participants), clinical trials which determine a drug’s safety and pharmacologic properties among healthy volunteers. Phase II. This phase tests a drug’s efficacy and optimal dosage. Typically 100-300 individuals…

Adjusted Risk Ratios

How do you estimate the specific risk a smoking has on the probability of being hospitalized.  If smokers on average have lower income and less educational achievement, is smoking truly causing the increase in hospitalization or could the covariates fully or partially explain the increased hospitalization rates? A paper by Kleinman and Norton suggests using…