The simple answer is no. Extra hours do not lead to higher productivity.

An analysis of figures from the OECD, a club of mostly rich countries, in 2013 found a negative correlation between GDP per hour and the number of hours worked across member countries.

Causation is unclear, it may be that workers in richer nations may feel they can take more time off. But, there is plenty of other evidence.

A study of munitions workers in the first world war found that their output per hour tended to decline once they spent over 50 hours a week toiling.

The Institute for Employment Studies, based in Britain, reviewed academic research on the subject and concluded that long hours working more than 48 hours a week was associated with (but was not proved to cause) various negative effects, including:

• Decreased productivity;
• Poor performance;
• Health problems; and
• Lower employee motivation.

It has been suggested that long hours lead to wasted effort or as C. Northcote Parkinson (a management theorist) suggested:

“…works expands to fill the time available.”

Reference

The Economist. (2018) Bartleby: Take a Break. The Economist. 24 November 2018, pp.56.