Background: Reference values of all the 21 psychosocial scales or dimensions (73 items) of the psychosocial risk assessment questionnaire COPSOQ ISTAS21 are computed from a representative sample of the wage earning population in Spain.
Methods: Representative sample of the Spanish wage-earning population, n=7,612. The sampling was multi-stage by conglomerates. The information was obtained by the administration of a standardized questionnaire in the household during 2004-2005. All 21 scales were standardized and three punctuation levels were established and labelled as 'more favourable to health (or green)', 'intermediate (or yellow)' and 'more unfavourable to health (or red)' according two criteria: 1) to obtain groups that follow a tertiles theoretical distribution and 2) to get the 'red' and 'green' groups as equilibrated as possible.
Results: Response rate was 60. Predictability dimension showed the wider difference between 'green' and 'red' proportions (7.14). Role clarity concentred the 35.06 % of population between 100 and 93.75 points, and Sense of community the 29.6% between 100 and 91.67. Double presence and hiding emotions grouped the 34.02% and the 27.74% % of population between 0 and 12.5 points, respectively.
Conclusions: 2005 upgraded representative reference values of the 21 COPSOQ ISTAS21 psychosocial dimensions for the wage earning population in Spain are available, necessary premise to diagnose risk situations and prioritize the needed preventive actions at company level.