OECD reports number of sick days for chronic diseases as follows: median number of sick days for; 0 chronic diseases, 1 chronic disease; 2 or more chronic diseases. To achieve better comparability between Norway and Europe, we have calculated and presented the mean number of sick days for people with one chronic disease and 2 or more chronic diseases. In order to measure robustness, we compared the calculated median sick days against the original variable and found negligible results.