Recommended: A systematic review shows no performance benefit of machine learning over logistic regression for clinical prediction models

This is one of those articles where you have to restrain yourself. Its message, that good old statistical tools like logistic regression can perform as well as these new fangled machine learning approaches that you haven’t taken the time to learn, is quite tempting. But I’d be cautious here. Maybe logistic regression is still competitive, but maybe the systematic overview got a bunch of biased studies. It’s worthwhile to cite this whenever someone makes an overly strong claim about machine learning models, but don’t use this as an excuse to keep from learning the new stuff yourself. This article is stuck behind a paywall. Sorry! Continue reading →

Recommended: Webinar Series, Congressionally Directed Medical Research Programs

We live in a golden age of learning, where you find find just about anything you’d ever need to learn from on the Internet. One example of this is a series of webinars about who to get research funding through the Congressionally Directed Medical Research Programs (CDRMP). I have not listened yet to any of these webinars, but they look like they would be very helpful for anyone seeking funding through this program. Continue reading →

Recommended: LaTeX/Mathematics

You can incorporate very nice looking mathematical formulas in R Markdown fairly easily. The system relies on LaTeX for displaying formulas and is surprisingly easy to learn. But every once in a while you want to do something a bit exotic, like placing a “hat” in your equation. I’ve typically just done a quick Google search on something like “LaTeX hat symbol” and each different search yields a different website. Recently, I stumbled up a fairly comprehensive guide to displaying mathematical formulas in LaTex. It is published as an eBook.

Note: Some of the examples require additional libraries like amsmath and I haven’t figured out yet how to take advantage of these libraries in R Markdown. Continue reading →

PMean: Slapping the word “pilot” on a failed study

Someone was asking on the MedStats listserv about a study that had gone off the rails. They had recruited only about a third of the patients that they had wanted. Things were going pretty well in the first arm of the study, but the second arm had a dropout rate of 50%.

Anyway, they decided to end the study (good call!) and wanted to know what they should do with the data that they had already collected. There were three options that they were considering (I’m paraphrasing a bit here).

  1. Analyze the study as originally planned, including a classic test of hypothesis for the primary outcome.
  2. Call this a pilot study and provide descriptive analyses only.
  3. Recognize that the data is so fatally flawed that any analysis of the data would be inappropriate.

This is what I suggested. Continue reading →

Quote: All scientific work is incomplete…

“All scientific work is incomplete, whether it be observational or experimental. All scientific work is liable to be upset or modified by advancing knowledge. That does not confer upon us a freedom to ignore the knowledge we already have, or to postpone the action that it appears to demand at a given time. Who knows, asked Robert Browning, but the world may end tonight? True, but on available evidence most of us make ready to commute on 8:30 the next day.” Sir Austin Bradford Hill, as quoted in his landmark 1965 paper on causation.