Japanese employees put in more time at work than perhaps anyone else in the world. The most extreme risk of this phenomena is “karoshi,” literally translated as “death by overwork,” which might account for thousands of deaths per year.

A new analysis examines a less extreme toll on both Japanese employees and businesses: lost work time from sick days and presenteeism. As a bonus, contrasting the Japanese case with US employees gives a glimpse into how unmanaged health issues can erode productivity.

The study finds that the average Japanese employee misses only about 2.6 days per year due to illness (including incidental absences and leaves of more than one month). But they have the equivalent of nearly 15 days of illness-related impairment on the job (i.e., presenteeism). Put another way, even with all the additional time that employees put in, Japanese businesses lose about 7% of their labor capacity due to impaired performance.

When the same number of US employees across similar industries (15,411 employees, about 2/3 of whom are in pharmaceutical manufacturers, most of the remainder in office furniture manufacturing) are processed according to IBI’s Full Cost Estimator (FCE) model, the opposite pattern is observed: presenteeism accounts for less lost work time than absence, only about 2% of US businesses' labor capacity. And despite the grueling work calendar of many Japanese workers, their average illness-related lost work time is 50% greater than in the US (18 days per-employee per year [PEPY] compared to 12 days, as seen in the chart below).

Sources: Japan sample: Chimed-Ochir et al 2019; US sample: Integrated Benefits Institute, 2019.

Note: PEPY = per employee per year; FCE = Integrated Benefits Institute’s Full Cost Estimator model


While the data and methods used in FCE and the Japanese study differ, the different lost work time patterns are hard to ignore. If we think of the Japanese workforce as particularly susceptible to extremes of a hard-charging corporate culture—examples of which can be found in every society, including the US—the lesson from the study becomes clear: even the hardest working employee has a finite ability to contribute on the job. Stress and overwork could complicate their struggles with chronic health symptoms such as pain, fatigue or psychological distress. They may put in more hours, but employers may be getting less productivity.