Effect of human variability on independent double: Reading in screening mammography

Rationale and Objectives. To demonstrate the range of gains and losses that radiologists might experience from independent double reading in screening mammography. Methods. From a national random sample of radiologists, the authors formed 131 pairs. For each radiologist, the authors analyzed the increase relative to his or her individual true-positive rate (TPR) or false-positive rate (FPR), number of additional cancers detected, and change to negative biopsy rate that would result from independent double reading after pairing. Results. The average radiologist can expect an 8%-14% gain in TPR and a 4%-10% increase in FPR with pairing. For some radiologists, double reading increased the TPR with a small concomitant increase in FPR. Other radiologists, however, realized small gains in TPR with large increases in FPR. Adding the reading from a more experienced radiologist did not necessarily improve the TPR of a radiologist with less experience. Conclusion, Radiologists can form complementary and noncomplementary pairs for double reading. Use of this procedure must be decided on an individual basis.