Thus we can make no assumptions about what is happening microscopically. This is true both because quantum mechanics is silent on what is happening and because these experiments are testing the correctness of quantum mechanics itself. To directly measure D requires that one have a high rate of singlet state events or a common trigger that controls these events and the change in polarizer angles. If this condition is not met the delay we measure will be dominated by the uncertainty in when a singlet state event occurs. If it will be impossible to accurately measure D .
Typical experiments involve distances of a few meters.
This correspond to expected values of ns. A high rate of singlet state events or a precise common trigger for singlet state events and changes in polarizer angles is necessary to discriminate between these times. One must show that a change in polarizer angles changes the probability of joint detections in less time than it would take light to travel from either detector to the more distant analyzer. There must be a macroscopic record to claim information has been transferred. It is the time of that record that must be used in determining if the information transfer was superluminal.