Date Published: April 24, 2007
Publisher: Public Library of Science
Author(s): Michael Callaham
Partial Text: We regret that in our paper in the January issue of PLoS Medicine , we failed to cite an important recent study  that validates a simple 5-point quality rating score virtually identical to the one we used, and which we find more efficient than scores with multiple subscales. We apologize for the omission of this helpful research.