# Cumulative Expected Method

#### Hakulienen Exact and Hakulinen Simplified

The exact and simplified adjustment in the calculation of expected survival
is described in detail in:

Hakulinen T, Abeywickrama KH. A computer
program package for relative survival analysis. *Computer
Programs in Biomedicine* 1985;19:197-207.

The simplified method approximates the exact calculation. Both options
are included in the program to allow for comparisons with existing software
that use one of the options when calculating expected survival.

#### Ederer I and Ederer II

Ederer I method calculates the expected survival
rates assuming each patient would be a member of the general population
from diagnosis to entire follow-up so the matched individuals are considered
to be at risk indefinitely.

Ederer II method calculates the expected survival
rates for patients under observation at each point of follow-up so the
matched individuals are considered to be at risk until the corresponding
cancer patient dies or is censored.

For more information on the Ederer methods, see
http://surveillance.cancer.gov/reports/tech2011.01.pdf.