[Correlative issues summary about time-to-event evaluation index in clinical observation]

The time-to-event index is a kind of common evaluation index. It measures the speed of intervention effect. It is different from other index in research design, source material filling, data checking and statistical analysis. To obtain the time-to-event index, investigators can fill in the table directly and statistical analyst can compute after clinical observation. When filling in the source material or data checking, it is should be noticed that the logical relation between the time-to-event index and the visiting point and between the time-to-event index and the correlative other indicator. When statistical analyzing, it is an important issue how to deal with the cases whose time-to-event index does not appear till the observation period ends. Understanding the difference clearly can make the time-to-event index evaluate the effect of the intervention truly and make the clinical observation results reliable.