This blog introduces you to funnel plots, guiding you through how to read them and what may cause them to look asymmetrical.
Is this study valid? Can I trust this study’s methods and design? Can I apply the results of this study to other contexts? Learn more about internal and external validity in research to help you answer these questions when you next look at a paper.
What is data dredging, how does it affect the p-value and what is its impact on the world around us?
Participants in clinical trials may exit the study prior to having their results collated; in this case, what do we do with their results?
Learn about the different types of sampling methods, examples of their uses, and potential sampling errors to avoid when conducting research.
When you see a claim that a treatment or intervention has no effect, it is important to examine the evidence as this may be a misleading statement.
The Catalogue of Bias (CoB), is a digital resource for clinicians, students, researchers, investigators, and consumers of health evidence. As of posting this blog, the catalogue has 49 published biases.
This blog is a critical appraisal of a randomized controlled trial, assessing the effectiveness of an early rehabilitation intervention to enhance recovery during hospital admission for an exacerbation of chronic respiratory disease.
Randomized controlled trials (RCTs) can be subject to different kinds of bias. Read about different sources of bias in this blog and how much the magnitude of effect can be changed by the presence of bias.
This blog is a critical appraisal of a randomized controlled assessing hydrotherapy versus conventional land-based exercise for the management of patients with osteoarthritis of the knee.
GRADE (Grading of Recommendations, Assessment, Development and Evaluation) is a prominent framework for evaluating the effectiveness of systematic reviews. This blog provides detail of the GRADE approach with useful links to further reading on this key process.
Publication bias remains a problem in health research. This blog by Andrés explores the issues we face and provides detail of the initiatives designed to address the problem.
This is the twenty-third blog in a series of 36 blogs explaining 36 key concepts we need to be able to understand to think critically about treatment claims.
Many fair comparisons never get published, and outcomes are sometimes left out. Those that do get published are more likely to report favourable results. As a consequence, reliance on published reports sometimes results in the beneficial effects of treatments being overestimated and the adverse effects being underestimated.
In this blog, Leonardo provides 5 interpretations that you should consider when you read or hear about a reported association in observational studies.
Debiasing is about trying to account for and eliminate the influence of biases on our decision-making. This blog discusses effective debiasing techniques.
This blog discusses fundamental issues affecting healthcare research, which could undermine the field and mean that most medical research may be wrong. Issues discussed include: 1) contradictory findings 2) the illusion of high impact factor journals 3) the reproducibility crisis 4) a lack of translation of research findings from bench to bedside 5) medical reversal 6) bias 7) statistical issues and 8) conflicts of interest and unethical practice. The author then explores possible solutions to these.
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.
Mechanical neck pain is prevalent in the general population. Adjusting the spine (spinal manipulative therapy) is complex and controversial, largely based on the Chiropractic concept of a joint “subluxation”. This blog is a critical appraisal of a study examining the acute effects of a single and multiple level thoracic manipulation on chronic mechanical neck pain.
This article highlights the importance of the results of Cochrane’s new systematic review on the efficacy of Methylphenidate for ADHD in children and adolescents.
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.
Does industry sponsorship of research inevitably lead to bias? And does this bias extend to government advice and policy?
After 8 long years of University education I have to admit that I still do it. What’s worse; I’ve even been known to do it for my own area of research. So why do I still Wikipedia when I can access the literature? And why I am becoming a Wikipedia editor for for the S4BE Editathon?
Do placebos really promote physiological change or is it just the patient’s perspective? How are placebos used in practice? And how ethical is it to use placebos in clinical trials?
Is this your first contact with evidence-based healthcare? This course is a perfect start…
Danny reviews the book Testing Treatments that aims to help everyone understand fair tests, how to ask questions and understand research.
Danny has reviewed the US Cochrane Center’s online course that aims to help you understand the basics of evidence-based healthcare and why it’s important.
Ammar takes a detailed look at CEBM’s evidence-based resources!
Reporting and discussing clinical trials clearly and accurately can be challenging, both for journalists, and also for students. Ruth Francis has compiled 11 top tips to make it easier.
Can probiotics prevent diarrhoea? A new Cochrane review says they can. This blog also walks through a few of the features of Cochrane reviews.
This tutorial teaches you about one of the biggest enemies of strong evidence in clinical research – bias, as well as measurements and outcomes in the clinical trial.
A meta-epidemiological study published in the BMJ last month has found that smaller trials consistently report larger effect sizes.
Critical appraisal is the process of carefully and systematically examining research to judge its trustworthiness, value and relevance in a particular context (Amanda Burls 2009).
An essay discussing the underpinnings of EBM and the difficulties of using it in clinical practice
AllTrials, putting the evidence back in evidence-based medicine.
PharmAware is a network of students committed to the use of the best evidence in healthcare.
Bias is often an issue within clinical research, and we take many measures to avoid it. However, these measures are often neglected in preclinical animal studies, which give us the results upon which clinical trial study designs are based.
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