Survey methods Weighting survey data to get population based estimates The different measures of work-related illness, workplace injury and working days lost. Measures of workplace injury: Definitions and formulae Measures of work-related illness: Definitions and formulae Measures of working days lost: Definitions and formulae Presentation of estimates Calculation of full-day equivalent working days lost estimates and rates Estimating working days lost due to work-related illness and workplace injury Converting reported working days lost into full-day equivalent working days lost Converting the number of workers into the number of full-time equivalent workers Sampling errors and confidence intervals Calculating confidence intervals around sample based survey estimates Reliability thresholds Calculating confidence intervals around sample based survey estimates of change Improving the precision of sample estimates by pooling annual data