I analyze the psychometric qualities of a screening instrument to predict depression after stroke using ROC analysis.
In this context, I read several papers which report an AUC without a p-value or an AUC with a 95% confidence interval including 0.50, for example: 0.48-0.72. However, the authors discuss the sensitivity and specificity of the instrument in these papers and conclude that e.g. the sensitivity is moderate/good.
Isn't it necessary for the AUC to be significantly different from 0.50, ascertained either by p < .05 or a CI not including .50, in order to conclude that there is any psychometric accuracy to the instrument? Or is it possible that an instrument shows good sensitivity and/or specificity while the AUC is not different from .50?