Sensitivity and specificity are those sorts of things that can really get knickers twisted up something rotten. They sound like something you should be able to understand, they get used as if you understand them, and then you realise … it’s not quite as you thought … Really diseased Really not diseased Test […]
Category: archimedes
Basics: Top 5 tips for evidence based paeds
Hot on the heels of my office next door neighbours SoMe course we’re off with a ‘Top Tips’ post. (Anyone who hates the cheesy format can comment below or tweet us @ADC_BMJ.) Please imagine a racing, 5-years-before-you’re-reading-this-pop-tune as your background music. 1. Know your question Know what you’re asking. And know why you’re asking it. […]
Diagnostic test accuracy
The main things we look for when examining a new diagnostic test are “Is it as good as, or better than our usual one”, “Is it quicker?”, “Is it cheaper?” and “It is easier for patients/less dangerous?” While the latter three questions can be assessed by asking the folk who do the test, asking the […]
Differential Diagnosis
The essential elements of a differential diagnosis study are, like most of critical appraisal, really simple and straightforward. You need to start with a bunch of children/young people who turn up with the symptom, or symptom-complex, you’re interested in. Ideally, you need these folk to not already be known to have something, to attend a […]
Things ‘ain’t what they used to be.
Grandma says it. Great-grandpa says it. Even the wife’s starting to say it. Its it true? Are things just not as good as they used to be? Well, while we will leave the greater political discussions to others (except to note the falling child mortality rates in most countries) we can focus on how drugs […]
Testing. Diagnostic tests – why?
“But what’s wrong with him, doctor?” The constant refrain from many a consulting room is not “How can you make her better?” but “Can you name the problem so I can own and understand it?”. When addressing this need we will each develop our own approaches; some of us will explore differentials, others state the […]
Basics. How much is enough?
We’ve approached EBM by thinking about it as a framework for thinking, not a checklist to tick though. It’s the combination of patients views, clinical expertise and relevant research. The process is of asking, acquiring, appraising, applying and assessing. But when it comes to applying evidence to answer a question – how much is enough? […]
Basics. RR, OR and the like
Just a few posts ago, we introduced the idea of NNT as being an ‘absolute’ measure of how effective a treatment is; that is, the number of folk needed to treat to get one extra good result, compared to something else. This can be used to balance against stuff that might be negative – such […]
How much should we believe in autonomy?
We’ll all remember that we are meant, with grown-ups, to allow the patient to make a choice about their care. When the patient is not really due to be in the atmosphere for another 2 months, and hasn’t quite learned to open its eyes rather let alone discuss UVC vs Groshong lines, then we’re sort […]
Basics. NNT
The NNT – number needed to treat – is thought by many to be a central core of EBMing. (I’d argue that the numbers in EBM are only a small part of the equation – and that understanding the question and the biases inherent in the study design are greater – but I’d still agree […]