Which inflation index should I use?

Many studies use data on health care costs from multiple time periods.  To make costs comparable over time, researchers often use an inflation index to translate previous years costs to current dollars.  The first question is, what inflation indices are available to make this adjustment.  A paper by Dunn et al. (2018) reviews the potential…

Cancer survival around the world

An interesting study measuring trends in cancer survival between 2000 and 2014 found, unsurprisingly, that patients in more developed countries had better survival. For women diagnosed with breast cancer between 2010 and 2014, 5-year survival rates reached 89.5% in Australia and 90.2% in the United States, but generally varied worldwide and remained low in some…

Which cancer treatment is best?

This seems like a straightforward question, but clearly depends on what you mean by “best”.  Some drugs will be more efficacious and have more adverse events; other drugs may be less efficacious but have fewer adverse events.  What if a one drug shows an 80% improvement in progression free survival (PFS), but a 50% improvement in overall…

Berkson’s paradox

Berkson’s paradox happens when given two independent events, if you only consider outcomes where at least one occurs, then they become negatively dependent.  More technically, this paradox occurs when there is ascertainment bias in a study design. Let me provide an example. Consider the case where patients can have diabetes or HIV.  Assume that patients have a positive probability of…

The problem with p-values

Interesting article in Aeon on why p-values may not be the best way to determine the probability we are observing a real effect in a study. Tests of statistical significance proceed by calculating the probability of making our observations (or the more extreme ones) if there were no real effect. This isn’t an assertion that…