Imitation, Contagion, or Exertion? Using a Tax Reform to Reveal How Colleagues' Sick Leaves Influence Worker Behaviour

We analyse the social interaction effects in sick-leave behaviour in the workplace, using high-quality Norwegian matched employer–employee data with detailed individual information on sick leaves during the 2004–2006 period. We find that social interaction effects in sick-leave behaviour in the workplace do exist, and that the effects are noticeable in size. The strong relationship between the sick-leave rates among colleagues is not solely the result of contagious diseases, nor is it caused by improved informational quality or by the increased workload for the non-absent workers. Evidence supports the existence of reciprocal worker behaviour that is unrelated to joint leisure-seeking activities.