Why do we need randomized trials?

Discussion about randomized controlled trials (RCT) has been extensive in social media during this spring due to corona virus epidemic. This discussion was especially heated when “not so good” clinical trial was published stating that hydroxychloroquine is efficient in the treatment of corona virus disease (CoViD-19). I drew this picture and posted it on Twitter. […]

Exploratory or confirming study?

Methodology is hard. And making valid inferences is very hard. With regard to these topics, orthopaedic research is not very different to other field in medicine. It means that misconceptions, misunderstandings and flawed approaches are prevalent also in our field. American Journal of Sports Medicine published recently two papers which both made a quite common, […]

Propensity scores, orthopaedics and shared decision making

This is something I posted on Twitter last October. Extended discussion can be found below the tweets Propensity score matching is often used when two cohorts of patient are compared. Aim is to have somewhat comparable groups so effect of treatment or intervention could be estimated reliably. In short, two groups of patient tread by […]

No evidence of no evidence

In the null hypothesis significance testing framework, failure to reject the null is never evidence in support of null. However, it is extremely common that failure to reject the null, ie. getting a p-value larger 0.05 is interpreted as “no difference” or “no evidence”. As many experts have said, “absence of evidence is not evidence […]