Non-identified response is a term used to signify censored observations in survival data, which are not independent of the endpoint of the interest. Such observations can happen for a variety of reasons:

* Misclassification of response; such as death from cancer, the response of interest, being erroneously misclassified as the death from another unrelated cause.

* Response happening causing prior censoring; such as relapse to heroin use causing the subject to quit a rehabilitation study to avoid the chemical detection.