Age-standardised rates

Differences in injury levels between regions will be partly due to the differences in underlying population structure. ‘Direct age-standardised rates’ have been calculated to enable comparisons to be made between geographical areas with different demographic characteristics, by controlling for the differences in the underlying population. Age-standardisation also allows for population changes within a region when comparing rates over time. Note, however, that age-standardised rates become unstable when small numbers are involved.

The age-standardised rate for an area is the number of injuries per 100,000 population that would occur in a ‘standard reference population’ (the ‘European Standard Population’ has been used), if that standard population had the age-specific rates (based on 5 year age-bands) of the population of interest.

We have not been able to generate a total Britain and Ireland average age-standardised rate for each injury type as each country separately supplied total injury numbers rather than numbers split by age-group. In the commentary, we have taken the decision to compare the regional rates either to each other or to the England average rate when there appear to be significant differences.