Association Between Time Spent Interpreting, Level of Confidence, and Accuracy of Screening Mammography

To examine the effect of time spent viewing images and level of confidence on a screening mammography test set on interpretive performance

Estimation of the effect of interventions that modify treatment

Motivated by a study of surgical operating time and post-operative outcomes for lung cancer, we consider the estimation of causal effects of continuous point-exposure treatments. To investigate causality, the standard paradigm postulates a series of treatment-specific counterfactual outcomes and establishes conditions under which we may learn about them from observational study data. While many choices are possible, causal effects are typically defined in terms of variation of the mean of counterfactual outcomes in hypothetical worlds in which specific treatment strategies are ‘applied’ to all individuals. For example, one might compare two worlds: one where each individual receives some specific dose and a second where each individual receives some other dose. For our motivating study, defining causal effects in this way corresponds to (hypothetical) interventions that could not conceivably be implemented in the real world. In this work, we consider an alternative, complimentary framework that investigates variation in the mean of counterfactual outcomes under hypothetical treatment strategies where each individual receives a treatment dose corresponding to that actually received but modified in some pre-specified way. Quantification of this variation is defined in terms of contrasts for specific interventions as well as in terms of the parameters of a new class of marginal structural mean models. Within this framework, we propose three estimators: an outcome regression estimator, an inverse probability of treatment weighted estimator and a doubly robust estimator. We illustrate the methods with an analysis of the motivating data.Fil: Haneuse, Sebastian. Harvard University; Estados UnidosFil: Rotnitzky, Andrea Gloria. Universidad Torcuato Di Tella. Departamento de Economía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Association Between Time Spent Interpreting, Level of Confidence, and Accuracy of Screening Mammography

PURPOSE: To examine the effect of time spent viewing images and level of confidence on a screening mammography test set on interpretive performance. MATERIALS AND METHODS: Radiologists from six mammography registries participated in the study and were randomized to interpret one of four test sets and complete 12 survey questions. Each test set had 109 cases of digitized four-view screening film-screen mammograms with prior comparison screening views. Viewing time for each case was defined as the cumulative time spent viewing all mammographic images before recording which visible feature, if any, was the “most significant finding”. Log-linear regression fit via GEE was used to test the effect of viewing time and level of confidence in the interpretation on test set sensitivity and false-positive rate. RESULTS: 119 radiologists completed a test set and contributed data on 11,484 interpretations. Radiologists spent more time viewing cases that had significant findings or for which they had less confidence in interpretation. Each additional minute of viewing time increased the probability of a true positive interpretation among cancer cases by 1.12 (95% CI: 1.06, 1.19, p<0.001), regardless of confidence in the assessment. Among radiologists who were ‘very confident’ in their assessment, each additional minute of viewing time increased the adjusted risk of a false positive interpretation among non-cancer cases by 1.42 (95% CI 1.21, 1.68), and this viewing-time effect diminished with decreasing confidence. CONCLUSIONS: Longer interpretation times and higher levels of confidence in the interpretation are both associated with higher sensitivity and false positive rates in mammography screening