The life table techniques are mainly applied in survival analysis, which deal with the expectation of occurrence of phenomenon according to time or the probability of occurrence of the events by time. The life table techniques were originally developed in the field of demography to express the duration of life experienced by a particular group of population during a particular period. The life table techniques may be applied to study the duration of stay of admitted patients in a mental institute (hospital stay tables). They may be applied to follow-up data of specific psychiatric patients maintained with certain specific drug/therapy (clinical life table). In hospital stay table, the admissions, patients remaining in the hospital, and the discharged cases are analogous to the births, living population, and deaths in the demography life table.