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.

Entries

Entry time of each exposure spell in years on one common scale.

Exits

Exit time of each spell (event or censoring); exits follow their entries.

Events

Events observed during exposure; zero yields a null rate.

Person-years

Total person-years of exposure across all spells.

Mean exposure

Mean person-years contributed per person.

Rate per 1000 PY

Incidence rate expressed per thousand person-years of exposure.

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.

• NLX Person Years Lived Calculator

  Compute the life-table person-years lived Lx as n times the average of lx and lx-next for an ordinary abridged interval, or as lx divided by nmx when the open terminal interval death rate is supplied.

• 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).

• 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.