Measures of workplace injury: Definitions and formulae

The LFS gives estimates on the levels of workplace injury.  All estimates are based on an individual’s most recent workplace injury in the 12 month reference period and exclude injuries caused by road accidents since they fall outside HSE’s jurisdiction.  Information is presented as estimated incidence and rates of reportable non-fatal injuries where:

• Estimated injury incidence is the estimated number of people reporting a workplace injury (excluding injuries caused by road accidents) in the 12 months prior to interview (the reference period);
• Injury incidence rate is defined as the injury incidence estimate divided by the annual estimate of employment (this is taken as the number of individuals reporting themselves as currently employed);
• Reportable non-fatal injury aligns the estimates with statutory reports of non-fatal workplace injury by employers and others under HSE’s Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RIDDOR), which whilst offering more depth suffers from under-reporting.  It includes those self-reported injuries resulting in 4 or more days off work.

The formulae used to calculate injury incidence estimates and rates for overall and individual characteristics such as age and sex are given by:

Incidence of non-fatal RIDDOR reportable  workplace injury	=	The estimated number of people with a non-fatal workplace injury (excluding injuries caused by road accidents) resulting in four days or more off work at any time during the 12 month reference period.
Incidence rate of non-fatal RIDDOR reportable workplace injury per 100 000 workers	=	The estimated number of people with a non-fatal workplace injury (excluding injuries caused by road accidents) resulting in four days or more off work at any time during the 12 month reference period Average number in employment in the 12 month reference period (taken as the estimated number of people currently employed in the LFS reference week)	x 100 000

For estimates by employment-related variables (such as occupation or industry) these formulae are refined slightly to account for the fact that the LFS only provides detailed information about the job in which the injury was sustained if it was the respondent’s current (including second job) or most recent job in the last 12 months.  [Although in estimates by employment-related variables, cases of injury sustained in the second job are excluded.  This is because the very small number of cases reported against the second job do not warrant the added complexity of allowing for second jobs in the calculations].  No job-related information is available for injuries sustained in other jobs.

Incidence of non-fatal RIDDOR reportable  workplace injury sustained in current or most recent job	=	The estimated number of people with a non-fatal workplace injury sustained in their current or most recent job (excluding injuries caused by road accidents) resulting in four days or more off work at any time during the 12 month reference period. Note: The job in which the injury was sustained may not be the current or most recent, but may still be a job in the last 12 months.  This information is not included in this incidence estimate
Incidence rate of non-fatal RIDDOR reportable workplace injury sustained in current or most recent job per 100 000 workers	=	The estimated number of people with a  non-fatal workplace injury sustained in their current or most recent job (excluding injuries caused by road accidents) resulting in four days or more off work at any time during the 12 month reference period Average number in employment in the 12 month reference period (taken as the estimated number of people currently employed in the LFS reference week)	x 100 000