Use this mortality or life-table method when age intervals, deaths, exposures, survivorship, and open-ended interval assumptions refer to the same population and period.

Age

Starting age of the interval in years.

Interval width

Interval width n in years.

lx

Life-table survivors at the start of the interval.

lx next

Survivors at the end of the interval; omitted for the open terminal interval.

Terminal m

Open terminal interval death rate m-omega; supplying it selects L-omega = l-omega / m-omega.

Lx

Person-years lived in the interval.

Interval type

Formula used: midpoint averaging or open-terminal rate division.

Life-table results depend on age grouping, exposure quality, the treatment of the first and terminal intervals, and assumptions about deaths within each interval. Sparse deaths can make rates unstable.

Complement a summary mortality result with age-specific death rates, survivorship, and exposure counts. A complete life table is preferable when the question involves several ages or remaining life expectancy.

• Person Years Exposed Risk Computation

  Sum exact exposure spells into total person-years lived at risk and convert an event count into the mean exposure per person and the incidence rate per thousand person-years.

• TX Total Years Lived Above Calculator

  Sum life-table person-years lived Lx over all intervals from a starting age upward to obtain the total years lived above that age.

• AX Average Years Dying Rule Calculator

  Compute the average person-years lived by those dying in an interval under the midpoint rule (a = n/2) or the Coale-Demeny infant rule (a0 = 0.07 + 1.7 m0), then convert the death rate to the life-table probability of dying q = n m / (1 + (n - a) m).