In a clinical trail with several visits, it is common to see volunteers not attending their visits at some time point for different reasons. I have these different situations, and I would like to know whether a certain term or phrase should be fittingly used in each case, the different conditions I have are:
- The participant didn't come, because he was not needed to come, he did come before and he is no more needed to attend.
- The participant didn't come, but he was needed to come, though he couldn't make it to come for whatever reason.
- The participant did attend, but the objective of his attendance was not fulfilled. For instance, the sample needed could not be collected or lost after collection. In effect the objective of his attendance was not completely achieved.
I know that there is a term for the second situation which is `drop-out', but how to use it with the correct punctuation? is it:
He was dropped out from the study at visit 10.
He dropped out from the study at visit 10.
He was a study drop-out at visit 10.