Unbiased Analysis of Today's Healthcare Issues

Rankings and Kendall’s W

How can you compare how similar two rankings are.  For instance, US News and Consumer Reports may both rate hospitals.  If they have identical ratings, then they are obviously the same.  However, what if the rankings differ for 2 hospitals?  For 4 hospitals?  How can one quantify the similar of rankings? One method for doing so […]

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Longer trials or larger sample size?

Developing drugs is expensive. Some estimates have estimated that the cost of bringing a drug to market is $1 billion. In addition, payers are now reimbursing based on the perceived value of a treatment. That is, treatments that provide more health benefits receive higher reimbursements. In this world of value-based pricing (VBP), pharmaceutical companies have […]

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Type I and Type II Errors for Dummies

In previous posts, I have describe in detail what constitutes Type I and Type II errors.  This figure, however, conveys the concept much more succinctly. HT: Marginal Revolution.

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Guidelines for indirect treatment comparisons

Is treatment A better than treatment B?  This questions is often difficult to answer, especially if there is not head-to-head evidence comparing the two treatments.  In other cases, however, one can use indirect evidence.  For instance, one randomized controlled trial (RCT) may compare treatment A to C (e.g., a placebo) and another trial can compare […]

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Increasing Generalizability of RCTs

Is your randomized controlled trial (RCT) generalizable to the general population?  This question is known as external validity and is a major issue for a number of treatments.  Sometimes, a treatment is very effective in an RCT, but less so in the real world. One reason why this may be the case is that the […]

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Measuring cause-specific mortality?

This question is not so easy to answer, even when using data from a randomized trial.  Further, many studies do not have the statistical power to identify cause-specific mortality.  Consider the following example from Kim and Thompson: Consider a trial of an intervention only influencing a single cause of death, or a few specific causes […]

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Beta Binomial Regression

Oftentimes, one will observe data cluster around two different points.  This distribution is known as a bimodal distribution.  A bimodal distribution could arise, for instance, when patients have two choices of health care providers, and the data measure the share of times patients use one of the providers. To model the effect of different covariates on variable […]

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Should we trust difference-in-difference estimators?

Difference-in-difference (DD) estimators are appropriate when the interventions are as good as random, conditional on time and group fixed effects.  Although much of the debate in the economic literature regarding DD estimators focuses on the possible endogeneity of the interventions, there is another problem with DD: underestimated standard errors. A paper by Bertrand, Duflo and […]

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How to implement propensity score matching

What options are available for propensity score matching algorithms?  Baser (2006) describes a number of popular options. Stratified Matching.  In this method, the range of variation of the propensity score is divided into intervals such that within each interval, treated and control units have, on average, the same propensity score. Differences in outcome measures between […]

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Local Instrumental Variables

What is the effect of a treatment on health outcomes?  The real question is: can you be more specific? Researchers may measure the treatment effect a variety of ways.  Sensible research questions include: What is the average effect of the treatment across all individuals? What is the average treatment effect only among those who received […]

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