Survival analysis is used when we need to choose a point in time to measure survival, success, failure, death, etc..
Two important concepts relate to the time that we observe the data. This is referred to as censoring and it comes in two varieties: left and right.
Left censoring happens when we do not know how many organizations, people, etc have failed before we began sampling. That means that we only see the people that have survived up to that point, and how long have they survived.
Right censoring happens when we do not know it the people survived and for how long beyond conclusion of the study.
Some techniques to look at survival analysis include:
- Hazard rate. This is the rate of not survivivngt to the midpoint of a specified time interval
- Cox Haphazard regression. This examines which IVs influence if failure occurred at a particular time. It is a proportional model, so time is not considered.
- A generic hazard model does not use proportion. So this model does think about how failure happens as a function of time.