Every session has an Output tab, on which you can customize miscellaneous settings that affect the appearance of the results matrix. In a Survival session, you can use the Output tab to edit the following settings.
These options let you specify whether rates in the results matrix will be displayed as percents or proportions, and to how many decimal places they will be rounded. Select the statistic type from the Display Statistics As drop-down list, and the precision from the Number of Decimal Places drop-down list. For example, if you select "Proportions" and "0.0001", the number 0.55555 will be displayed as 0.5556 in the results matrix. If you select "Percents" and "0.01%", it will be displayed as "55.56%".
Once you have set the statistic type and precision, you may click the Set Defaults button if you want to use these settings automatically each time you create a new Survival Session.
Select this option to flag all cumulative relative survival rate standard errors greater than the specified percent. This flag affects all cumulative summary and survival life pages. If the standard error is not displayed as a percentage, then you must multiply it by 100 in order to compare it to the flag value.
This option allows you to suppress the display of statistics on survival life pages that are based on fewer than a specified minimum number of cases entering the first interval. The affected survival life pages will appear in the survival matrix but will be empty. The empty pages are left in the final matrix in order to properly document which pages were suppressed.
When calculating relative survival, the rates can be calculated properly and yet be greater than 1.00. This occurs when the actual observed survival for the case cohort has a higher survival rate than the expected rates for that same age, race, sex and date at which age was coded.
When this box is checked, any calculated relative rate which exceeds 1.00 will be adjusted down to 1.00 on the output tables.
Sometimes the cumulative relative survival rates can be calculated properly and yet be increasing over time, making it appear as if people are rising from the dead. This occurs when the actual observed survival for the case cohort decreases more slowly than the expected rates for that same age, race, sex, and year group.
When this box is checked, any cumulative relative survival rate which exceeds the rate in the previous interval will be adjusted down to equal the previous rate.
Unadjusted expected survival rates do not account for the possibility that the potential follow-up times of patients are of unequal length. Unequal potential follow-up time affects the estimate of expected heterogeneity between patients diagnosed in different calendar years (i.e. if the distribution of race, sex, or age change over time). 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.