![\"20140205-091454.jpg\"](\"https:\/\/blogs.bmj.com\/adc\/files\/2014\/02\/20140205-091454.jpg\")
<\/a>\nAfter a short pause while brain cells were diverted elsewhere<\/a>, we’re returning with the critically acclaimed (well, slightly positively tweeted) StatsMiniBlog series.<\/p>\n
(As an aside – do let me know via comments, Facebook or Twitter if there’s an issue you’d like to see covered)<\/p>\n
Kappa (\u03ba) is a measure of agreement, usually between two observers of a dichotomous outcome although there are variants for multiple observers. \u00a0It gives you a measure of what agreement you see that is ‘beyond chance’<\/p>\n
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The idea is that if you got two observers\u00a0to report on the colour of\u00a0balls emerging from a bag, and in reality there were 5 blue and 5 yellow,\u00a0if the\u00a0observers didn’t look at them and just guessed you would expect them both to be right 0.5 * 0.5 = 0.25 (25%) of the time.<\/p>\n
Anything over this is “agreement beyond chance”.<\/p>\n
The value given to Kappa reflects the degree of agreement, 0 is perfect disagreement, 1, perfect agreement, in between is usually interpreted<\/p>\n