Sunday, June 5, 2016

Clinicians' wisdom of crowds

The Wisdom of Crowds of Doctors: Their Average Predictions Outperform Their Individual Ones

The book on "Wisdom of crowds" became popular claiming that  the aggregation of information in groups achieved decisions that are often better than could have been made by any single member of the group. Now in Medical Decision Making you'll find an article that applies such reasoning to clinicians. And it says:
Little research has been done on whether the average of clinicians making predictions is more accurate than the individual clinicians themselves or whether their average prediction compared favorably to statistical predictions. The purpose of the present study is to examine the predictive accuracy of the average of individual clinician predictions and to compare this average to the accuracies of individual clinicians and to a published statistical model.
And the four conclusions are:
First, it would appear that the averages of the clinicians perform better than clinicians individually. All the clinicians on their own performed with a concordance index of 0.628. However, averaging the predictions of just a pair of clinicians had better performance. Second, the performance tends to improve as more clinician predictions are averaged. Interestingly, at least in this study of a limited number of clinicians, although performance was seen to continually improve as clinicians were added, there was decreasing marginal return for increasing group sizes. Third, as the group size increased (see Figure 2), the performance of the averaged clinicians approached that of the best individual clinician (from Figure 1), suggesting that much larger clinician groups are needed for the performance of the average to be better than that of the best clinician. And fourth, even averaging all of the clinicians’ predictions was inferior to that of the statistical model.
The authors recognise their study limitations, however some insights are useful to take into account. Let's ponder on how many "second opinions" would be approppriate.

This Wednesday at Saló del Tinell in Barcelona, great concert by Capella de Ministrers on Ramon Llull,the last pilgrimage

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