The Impact of Fatigue on Satisfaction of Search in Chest Radiography

Abstract

Rationale and objectives: To assess the nature of the satisfaction of search (SOS) effect in chest radiography when observers are fatigued; determine if we could replicate recent findings that have documented the nature of the SOS effect to be due to a threshold shift rather than a change in diagnostic accuracy as in earlier film-based studies.

Materials and methods: Nearing or at the end of a clinical workday, 20 radiologists read 64 chest images twice, once with and once without the addition of a simulated pulmonary nodule. Half of the images had different types of "test" abnormalities. Decision thresholds were analyzed using the center of the range of false-positive (FP) and true-positive (TP) fractions associated with each receiver operating characteristic (ROC) point for reporting test abnormalities. Detection accuracy was assessed with ROC technique and inspection time was recorded.

Results: The SOS effect was confirmed to be a reduction in willingness to respond (threshold shift). The center of the FP range was significantly reduced (FP = 0.10 without added nodules, FP = 0.05 with added nodules, F(1,18) = 19.85, P = 0.0003). The center of the TP range was significantly reduced (TP = 0.39 without added nodules, TP = 0.33 with added nodules, F(1,18) = 10.81, P = 0.004).

Conclusions: This study suggests that fatigue does not change the nature of the SOS effect, but rather may be additive with the SOS effect. SOS reduces both TP and FP responses, whereas fatigue reduces TPs more than FPs.

Keywords: Satisfaction of search; accuracy; fatigue; performance.

Figure 1

Example of one of the cases used in the study, showing as the native abnormality a right middle lung collapse (white arrow) in the non-SOS (top without added nodule) and SOS (bottom with added nodule indicated by the black arrow) conditions.

Figure 2

Average ROC points associated with non-nodule reports for faculty and residents in the non-SOS and SOS conditions (each point is the average of 10 readers).