Background Increasing work participation is an important political objective in many countries. In Norway, a voluntary national intervention program aimed at increasing work participation (the IA Agreement) was implemented in 2001, and is still ongoing. One of the main goals of the IA Agreement is to reduce sickness absence (SA) and disability pensions (DP). Organisations that sign the agreement commit themselves to take active measures in order to reduce SA and DP, and in return, they are given special rights such as grants for workplace adjustments and job training. Scientific evaluations of the IA Agreement have been limited. We aim to estimate the impact of the IA Agreement on SA and DP in Norway during 2001–2009.

Methods The source population is a national cohort of all 626 928 individuals born 1967–1976. Individual-level data on SA, DP, employment, and background characteristics were obtained from national registries. We apply a quasi-experimental design using difference-in-difference analysis, comparing employees in IA organisations (intervention group) with employees in non-IA organisations (control group), with respect to pre-post differences in SA and DP.

Results The IA Agreement was signed by 13 760 organisations by March 2003 and covered 43% of Norwegian employees. Compared to the general working population, IA organisations had a higher proportion of women and workers in the healthcare sector. We will analyse the nationwide impact of the IA Agreement on SA and DP and explore differences by gender, industry and diagnostic category.