Lipsitch M, Tchetgen Tchetgen E, Cohen T. Negative controls: a tool for detecting confounding and bias in observational studies. Epidemiology. 2010;21:383–388.
The sentence beginning at the bottom of page 386 should read: “If A and B are perfectly U-comparable and B does not cause Y, then a null finding of B-Y means that the A-Y association is unbiased.”
In the published version, the phrase “null finding of B-Y” was written incorrectly as “null finding of A-N.”