This paper assesses the causal effect of sick-leaves on subsequent earnings using an administrative dataset for Norway linking individual earnings, sick-leave records and primary care physicians. The leniency of a worker's physician - certifying sickness absence - is used as instrument for sick-leaves. Sick-leaves have a substantial impact on future earnings, reducing earnings by .3 percent per day of absence. When conditioning on full-time employment also two years after sickness the effect is .06 percent per day of absence. These effects are persistent over time and work mainly through wages not hours.
sickness absence wage formation IV estimation wage regression