As its summer time & thoughts of exciting summer camps expanding skills, or time spent catching up with missed opportunities, or indeed just beer & strawberries, are filling our lives it seems appropriate to go entirely left field and explore confidence intervals. Confidence intervals describe – in terms of interpretation – the range of values […]
Latest articles
Basics: AVID
The shortcut world of acronyms for critical appraisal was lacking one for diagnostic test accuracy – we have RAMbo for RCTs, FAST for systematic reviews, but what of the poor reader of studies evaluating a new test? We know the basic idea – patients who are considered to potentially have the diagnosis in question have […]
StatsMiniBlog: Calibration vs Discrimination
There are a variety of clinical prediction rules in the world. If you’ve seen one – they always used to have a nomogram attached – it would take the answers to a few questions and come up with a ‘probability of bad thing happening’. As we’ve mentioned previously, there’s an issue with deriving models and assuming they will work […]
Basics: CASP checklists
The basics of evidence based medicine are to ask a question, acquire a paper that might answer it, appraise the study, apply it’s results and assess performance. The appraisal bit can be done a few different ways – but underneath nearly all of them sits a similarity of key concepts – it’s just the gloss that varies. […]
Predictive Factors
Sometimes, we spot stuff that predicts how things will happen. Well, usually happen. These may be described as ‘risk’ factors – that is, factors which predict something will happen – or ‘prognostic’ factors – thinks that predict the outcome of a condition. There are a range of generalisations that are sometimes made from ‘predictive’ studies, […]
Practical Authorship: What to write instead of a Case Report
I’ve spent quite a while trying to convince you that you really ought not to be writing a case report. But you’re in a bind. Firstly, you’ve got in mind a case report – or you’re under pressure to write a case report with (for) someone. And also, you’ve got to get published. So, what […]
Stopping Rules
If you were cycling or driving, you’d probably know what the stopping rules were. Traffic not moving, big red sign, large goose with malevolent glare (Lincolnshire speciality). What if you’re doing a clinical trial? There are a variety of things what have been described, some of them are qualitative (SUSAR – sudden, unexpected, serious adverse […]
There are many ways to truss a duck
And there are lots of ways to do ‘synthesis’ of evidence within a systematic review. We’ve gone on – at length – about meta-analysis and described qualitative synthesis with meta-ethnography, but in a new paper in the Archives we see how a narrative combination of quantitative research studies with a qualitative framework to understand them can […]
StatsMiniBlog: Bonferroni Correction
The Bonferroni Correction is the simplest, the most understandable, and the most extreme way of correcting for multiple statistical tests. You take your ‘significance’ level and divide by the number of tests you are doing. So if you have set ‘significance’ at 0.05, and do 5 different statistical tests, to be actually sure that your “rejection […]
Why are you measuring it like that?
We measure, monitor and assess lots of things in our jobs. We frequently try hard not to think about poorly reproducible some things are – take breathlessness in children as discussed in a recent blog – and the whole literature is methodologically far weaker than that of intervention research. Sometimes we’re really like to assess something, […]