“Long working hours are leading to a rise in premature deaths, the W.H.O. says.”

In light of recent news by the World Health Organization and the LIO i’m republishing some collected thoughts and research around developer productivity.

Quality

The quality of software is directly influenced by developer’s fatigue. The work of an engineer is completely mental and a tired engineer does not deliver the same results, worse still, they might be introducing potentially dangerous bugs.

When used long-term, Crunch Mode slows development and creates more bugs when compared with 40-hour weeks.

More than a century of studies show that long-term useful worker output is maximized near a five-day, 40-hour workweek.

Henry Ford experiments conducted over 12 years showed  that cutting the workday from ten hours to eight hours — and the workweek from six days to five days — increased total worker output and reduced production cost. 1

Long weekly hours and long daily hours do not necessarily yield high output.
employees at work for a long time may experience fatigue or stress that not only reduces his or her productivity but also increases the probability of errors, accidents, and sickness that impose costs on the employer. 2

Health

Tired engineers risk damaging their health.

...overtime is defined as more than 40 hours per week and ..

.. extended work shifts are defined as shifts longer than 8 hours …

On 75 studies across all continents and industries … overtime was associated with poorer perceived general health, increased injury rates, more illnesses, or increased mortality in 16 of 22 studies. 3

A 12 year study in Australia … covering 13,000 individuals … noted a 48% increased probability regarding mental health decline in those workers working 49–59 hours per week, compared with those under standard working hours (that is, 35–40 hours per week).

There were greater declines in mental health in relation to longer working hours among persons in higher compared to lower occupational skill levels. 4

Results revealed a 267% increase in depression symptoms and a 284% increase in anxiety symptoms among those female workers working more than 55 hours per week, compared with those under standard working hours (35–40 hours per week)5

A 30-year longitudinal study in Denmark of 5,249 employed Caucasian men aged 40–59 years showed that men working 41–45 hours per week had a 59% increased risk of mortality due to ischemic heart disease compared to men working less than 40 hours per week.

Researchers analyzed the relationship between serious disease and hours worked over a 32-year period. Employers and government regulators should be aware of the risks, especially to women who are required to regularly toil beyond a 40-hour work week. Companies benefit in terms of quality of work and medical costs when their workers are healthier, men who worked moderately long hours (41 to 50 hours weekly) had lower risk of heart disease, lung disease and depression than those who worked 40 hours or fewer. 6

A reduction of working time is associated with a drop in the probability of smoking, in alcohol consumption, and in physical inactivity. 7

Performance

Relationship between weekly hours worked and performance among 5000 managers and employees … working longer hours between 30 and 50 hours a week lifts performance.

But for people working 43 hours, adding 7 hours per week to persons with low passion-purpose predicts an addition of 1.5% to their performance ranking.8

Productivity

There is an inverse correlation between hours worked and productivity. 9

Sometimes you have to crunch and work overtime. While that can give you a productivity boost and help you get needed things done, in the long term—past four weeks—long work weeks actually make us accomplish less.10

Illinois Institute of Technology professors Van Zelst and Kerr surveyed their colleagues’ work habits and schedules. If you expected a correlation between the hours scientists worked, and the number of articles they published, you would be mistaken. The curve rose steeply at first and peaked at between 10-20 hours per week. Then it turned downward so that scientists who spent twenty-five hours in the workplace were no more productive than those who spent five.11

For example, an overworked employee may very well be just as productive (or almost as productive) during his or her first, say, 4 hours of work while working 60 hour weeks as he or she was while working 40 hour weeks. However, it may be the case that productivity drops dramatically after say, 8 hours of work; in fact, productivity may drop so much after some point as to become negative. 12

Anecdotes

Google. When I started as an L3, I worked the standard 8 hour day on most days.
Today, I probably put in 10 hours a day. In by 7am, out by 5:30, with an hour gym time in the middle.

Most people are at their desks around 9 and most of us are headed home between 5 and 6.

If you have to work more than that, then you probably bit off more than you can chew. 13

Recommendations

Match Passion and Purpose

Managers and employees who matched passion and purpose performed far better than those who didn’t .. 18 percentile points higher than those who didn't in our 5000 person dataset … getting more done in each hour of work (and they don’t work many extra hours). 14

Work from anywhere

A private room at home, at least six-month tenure with Ctrip, and decent broadband access as conditions.
…
Work-from-home employees work a true full-shift (or more)
…
Employee attrition decreased by 50 percent among the telecommuters, they took shorter breaks, had fewer sick days, and took less time off.
…
The sum total of the research led Bloom to recommend going for it with work from home but enabling it just a few days a week versus its being a constant. 15

After the pandemic experience we can now be certain that working from anywhere can bring big productivity boosts.

Ditching the office at least part-time can boost profitability and personal happiness—provided it’s done right. 16