National data has advantages like comparability between areas and standard indicators/targets, but local data provides more granular, timely, and useful information for public health. Local data sources in Somerset include population statistics, lifestyle surveys, screening and vaccination rates, deprivation indices, and disease registers from general practices. Examples shown how local cervical cancer and childhood vaccination data can identify poorly performing areas for intervention, and how smoking and deprivation data were used to target communities for smoking cessation programs.