An MP-SIR results matrix consists of Standardized Incidence Ratio tables which provide the following statistics for your cohort. The display of these statistics may be enabled or suppressed on an individual basis using the Matrix Options dialog.

**Observed**- The actual count of events experienced for this subset of your cohort.**Expected**- The number of events expected to be experienced, based on the data in your referent rate file and accumulated*person time at risk*for this subset of your cohort.**O/E**- The Observed count divided by the Expected count.**Conf Ints**- This check box enables display of two columns, labeled CI Lower and CI Upper, which indicate the lower and upper bounds of the confidence interval (as defined on the session's Statistic tab) for the O/E statistic.**Excess Risk**- Excess cancers (beyond the expected amount) per 10,000 persons per year. The formula for excess risk is:

((Observed count - Expected count) x 10,000) / Person years at risk

**Note:** For sex-specific sites, the excess risk statistic will be incorrect if the person years at risk is not sex-specific. For example, if showing statistics by cancer site and sex, the statistics for both sexes combined for sites such as prostate, cervix, etc. will be incorrect.

**Persons**- The number of persons in this subset of your cohort.**Person Yrs at Risk**- Person time at risk contributed by this subset of your cohort, expressed in years.**Mean Pers Yrs Risk**- The mean person years at risk contributed by each individual in this subset of your cohort.**Mean Age at Exposure**- The mean age at exposure, in years, among individuals in this subset of your cohort.**Mean Date of Exposure**- The mean date of exposure among individuals in this subset of your cohort. Dates are expressed as calendar years, using decimal places.**Mean Age at Event**- The mean age, in years, at the time of experiencing an event among individuals in this subset of your cohort.**Mean Date of Event**- The mean date at the time of experiencing an event among individuals in this subset of your cohort. Dates are expressed as calendar years, using decimal places.