Additionally, in itinere accidents (going to or returning from work) and nontraumatic injuries (e.g. heart attacks) are not considered, as their relation to occupational hazards is not direct. Those individuals who declare having an unwritten contract are also excluded.
However, possible endogeneity problems still remain unsolved. If the incidence rate is used as a proxy of occupational risk we won‘t be able to distinguish between risk as the cause of concentration of immigrants or, the other way round, the concentration of
immigrants as the cause of risk. As discussed in the previous section, many authors claim that lack of language skills and differences in cultural background may undermine prevention polices effectiveness. If this is true, immigrants‘ overrepresentation in certain
occupations could be responsible for the higher injuries rates observed. To avoid
endogeneity problems we need a risk measure that captures workers‘ exposure to hazards, but it is not related to occupational fatality rate.