Survival Factor (p(a)) in Life Tables: Definition and Interpretation

The fraction p(a), which we may speak of as the survival factor, is a measure of the probability, at birth, that a random individual of the batch shall reach age 'a', under the conditions under which the data assembled in the life table were collected. In simpler terms, the survival factor represents the chance of an individual surviving to a certain age based on the data collected for that specific population group.