StatsMiniBlog: I-squared

No, not -1, the self-multiplication of that fancy imaginary number that helps aircraft designers make wings work properly, but a (semi) quantitative assessment of how much heterogeneity there is in a meta-analysis: I² You’ll recall that the idea of heterogeneity (mixed-up-ness) comes in both statistical and clinical flavours. This measure – I² – assesses the statistical […]

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StatsMiniBlog: Cluster analysis

Lumps and groups and clumps and factors … all sorts of ways of describing how Things Can Be Similar. Cluster analysis is a statistical term that refers to an approach – not a particular method – that seeks to work out how to group items together so those in the same group are maximally similar […]

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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 […]

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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 […]

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StatsMiniBlog: Confidence Intervals

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 […]

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StatsMiniBlog: Stepped Wedge Trials

You may be wondering about the phrase “Stepped Wedge Trial” (SWT) as there haven’t been many in paediatrics. (There is quite a nice one about the provision of free school breakfasts though – showed that giving free breakfast didn’t really improve attendance, or test scores, but the children didn’t feel as hungry.) They are a […]

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