Furthermore, metadata should specify (i) whether the data relate to cases of occupational injury which have been reported (to an accident notification system or to an accident compensation scheme), compensated (by an accident insurance scheme) or identified in some other way (for example through a survey of households or establishments) and (ii) whether cases of occupational injury due to commuting accidents are included in the statistics. Metadata should also specify the worker coverage according to the economic activity (ISIC), institutional sectors and status in employment, information on occupations for which data on accidents at work are subject to confidentiality by national legislation, as well as procedures used to correct data for under-reporting (or over-reporting). Finally, information about any national specificity essential for the interpretation, i.e., description of the work insurance system for reporting accidents at work, discrepancies between national and international definitions (e.g., definition of local unit, commuting accidents, etc.) Because data quality issues may be present, it may be more relevant to analyse indicator trends rather than levels.