How is "coverage" defined for occupational health services?

The proportion of workers receiving occupational health services (OHS), or OHS coverage, is considered an important indicator in the evaluation of the national OHS levels. Although the term "coverage" is used in some papers, the definition of the term appears to vary from author to author. Despite vague definitions of the term, the issue has not been much studied. It appears that this vagueness has not led to attempts to establish a clear definition of the term. This study, was undertaken to clarify the meaning of "coverage" when used in relation to OHS. Papers using "coverage" as an indicator of the OHS levels or discussing the issue were collected and analyzed. The first aspect examined concerned the definition of "coverage." Next, the denominator (the target population), and methods for estimating the numerator (the number of workers provided with OHS) were described according to this definition. Few papers dealing with OHS coverage provided an explicit definition: none of the papers stated clearly the OHS functions encompassed when considering coverage, using simply the term in the context. Nor was the worker category to be represented in the denominator discussed, e.g. employees only, or the entire working population. The method for estimating the numerator was generally undefined. This study makes it clear that the term "coverage" in relation to OHS is currently used without clear definition. To permit objective assessments of the national OHS levels, "coverage" must be defined in terms of three elements: OHS functions, the numerator and the denominator of the proportion representing the extent of OHS coverage.