• Occupation
• social class
• social mechanisms
• occupational epidemiology
• epidemiology
• mental health
• sociology
• psychology
• public health

The recent paper by Ferrario et al 1 as well as the follow-up comment by Kawada2 contributes to a persisting confusion in occupational and social epidemiology, namely, the conflation of the constructs of ‘occupation’ and ‘social class’. Clarifying this confusion begins with acknowledging that occupation and social class are two distinct constructs that lead to different social stratification hypotheses, social mechanisms and intervention strategies with regard to health inequalities.3–5 While occupation refers to the technical aspects of work (eg, a taxicab driver transports passengers between locations, a lawyer practices the system of rules of conduct established by society), social class refers mostly to employment relations in the labour market according to control of productive assets (eg, owner, self-employed), organisational assets (eg, manager, supervisor, frontline worker) and skills in short supply (eg, postgraduate education, college degree, high school diploma).4 ,5

There is an intuitive appeal to using occupation as a social class marker or to conflate the two constructs. Both dimensions are important indicators of social inequality. Greater precision, however, is needed to disentangle the gradational and relational aspects of occupation and social class. From a gradational perspective, occupations are ranked hierarchically along various factors (eg, job title, employment industry) to produce graded schemas (eg, manual workers vs professionals). CEOs, bankers and hedge fund brokers are viewed simply as professionals when, in fact, each occupation also implies an important class position (owner, manager and worker). In relational terms, the concept of social class emphasises societal divisions based on ownership and non-ownership of productive resources. For example, a ‘cab driver’ could be a worker for a cab company, a self-employed owner of a cab, a manager of a taxicab fleet, an owner of a taxicab fleet or any combination of these positions. Because occupational classifications only capture the technical information of being a cab driver, they provide little information on the power relations at work that generate health inequalities.

Occupation and social class approaches lead to different hypotheses on the association between social stratification and health inequalities. Conceptualising stratification using occupation leads to ‘gradient’ predictions. Conversely, a focus on social class and employment relations broadens the analytical scope to include ‘non-gradient’ hypotheses.4 ,5 Since class locations represent the interaction of different means of production, organisational and skill assets, contradictory class locations6 emerge which lead to counter intuitive findings. For example, managers who are non-owners of productive resources are expected to enjoy better health compared with small business owners and supervisors who possess more organisational assets compared with frontline workers are hypothesised to experience worse health.4 ,5

Hundreds of studies in social epidemiology have shown differences between ‘occupational social classes’. However, the majority of these studies provide little insight on how economic and power relations and mechanisms operate at the workplace to produce health inequalities.7 It is, therefore, not surprising that the use of ‘occupational social class’ continues to generate uneasiness among occupational epidemiologists.2 The conclusion is straightforward: a greater effort is needed to theorise, conceptualise and measure ‘class’ in relational terms in occupational epidemiology.