Saul Crandon provides an overview of Case-control and Cohort studies: what are they, how are they different, and what are the pros and cons you need to consider in each study design.
This blog is a Portuguese translation of the blog ‘The bias of language’ by Katherine Stagg. Read the English version here. With thanks to Cochrane Brazil for the translation.
This blog is a Portuguese translation of the blog ‘Defining Bias’ written by Dabean Faraj. Thanks to Cochrane Brazil for the translation.
This blog takes a detailed look at the issue of attrition bias (bias that can arise when participants drop out of a study). It also describes measures that can be taken by researchers to minimize this bias (including different types of statistical analyses).
This blog discusses the problem of confirmation bias: our tendency to favour answers that confirm ideas and beliefs that we already have. It also discusses two possible solutions to this problem: 1) referring to systematic reviews, which take account of ALL the available evidence and 2) actively seeking out information which may challenge our preconceptions.
This blog explains what allocation concealment is & why it’s important, in terms of preventing researchers from (intentionally or otherwise) influencing which participants are assigned to a given intervention group.
Outcome switching is a major problem in clinical trial reporting that distorts the evidence doctors and patients use to make real-world clinical decisions. Numerous prevalence studies have already shown this to be an extremely common problem, even in top medical journals. However the CEBM Outcome Monitoring Project (COMPare) has taken a new approach: writing to journals to correct the record on individual trials, in the hope that individual accountability and open data sharing will help solve this important problem. Our main question was: how will the journals respond? This blog tells the story of COMPare so far.
A brief overview of the concept of bias and what it means. This blog also describes 2 particular types of bias that are perhaps less well known to students.
Katherine Stagg explores the impact of language bias and how the language of publications can affect our evidence base.
Deevia takes a look at ‘effect modification’ and ‘confounding’ and explains the differences.
In his book, A Scientist in Wonderland, Edzard Ernst describes his life and career. He becomes a pioneer in researching alternative medicine, and as one would expect, makes plenty of enemies along the way.
Does industry sponsorship of research inevitably lead to bias? And does this bias extend to government advice and policy?
In his new book, Dr. Goldacre continues his crusade of exposing quacks and pseudoscience, with an emphasis on how journalists totally mislead the public about what a scientific paper really says. He also chronicles his AllTrials quest by railing against the lack of transparency in clinical trials and publication bias.
In Richard’s Reviews this week, we look at progress in sharing clinical trial data through the All Trials campaign, and the nature of patient-centred outcomes research.