Thursday, June 28, 2012

The secret life of trials....


When trials disagree...it can get ugly! But going into meta-analysis could help sort things out.

For a meta-analysis - a technique for combining the results of multiple trials - trials have to pretty much belong together. Differences might be responsible for contradictory results - including differences in the people in the trials, the way they were treated, or the way the trials were done. That's called heterogeneity. Too much of it, and the trials shouldn't be together. But heterogeneity isn't always a deal breaker.

Want to read more about heterogeneity in systematic reviews? Here's an article by Paul Glasziou and Sharon Sanders from Statistics in Medicine. Or try the open learning materials from the Cochrane Collaboration.



Monday, June 18, 2012

Promising = over-hyped + under-tested



I first wrote about the tendency of "promising" treatments to metamorphose into "disappointing" treatments in a BMJ piece about evidence based mistakes. Early results, after all, can't promise anything at all.


The graph depicts a cumulative meta-analysis: each new study is being absorbed into a summation of the evidence so far. With 4 studies, it's shifted from the "this helps" side of the ledger over to the "this harms" side. See more about cumulative analyses in this classic article.


"Promising" is primarily a media and marketing staple, of course. Several wonderful initiatives keep the media to account on this, story by story: Behind the Headlines, the wonderful US Health News Review - and the other related "Media Doctors" in several countries.

Wednesday, June 13, 2012

Begging hopefully for less bias


From my guest blog post at Scientific American - Holy sacred cow!

Personal bias, wishful thinking plus biased research results is one recipe for a sacred cow. If more rigorous research results in a conflicting message, it could cause cognitive dissonance - and the less biased research often faces an uphill battle for acceptance.

And I also wrote about the importance of being just as rigorous about the claims we want to believe as those we're skeptical of here at the British Journal of Sports Medicine blog.

If you want to get better at critically assessing health claims, Smart Health Choices is a great place to start.

Wednesday, June 6, 2012

The trial acronymania menace


As if there's not enough for us to remember, we're supposed to remember endless acronyms for trials too now. There's even a wiki to help us keep them straight and a call for a register of trial acronyms to reduce multiple use of all the words ending in T! Somewhere along the line this became marketing: not much equipoise in ACHIEVE, MIRACLE or PROMISE, eh? A study has classified this as a form of coercion. Ivan Oransky called for a HALT (Help Acronyms Leave Trials). If you're irritated by the next outbreak of trial acronymania or acronymesis you come across, you're not alone!