In the article by Collier et al in the April 2009 issue of Arthritis Care & Research (pp. 496–500), the key for Figure 4 was incorrect. The key for A should have read, (filled squares) MD Prediction Does Not Concur With DAS28, (open squares) MD Prediction Concurs With DAS28; and the key for B should have read (filled squares) DAS28 Does Not Concur With MD Prediction, (open squares) DAS28 Concurs With MD prediction. This has been corrected in the online version of the article (

We regret the error.