Self-help books about the subject fly off shelves, enterprises embrace process-improvement doctrines with cultish zeal, and we spend collective billions on technologies that promise to make us more effective. The irony of this obsession is that one of the main behaviors it elicits—working longer hours—is fundamentally unproductive. Some of the reasons are intuitively obvious; overwork strains the happiness and wellbeing of employees which can lead to reduced motivation and expensive turnover. However, there is a well-established body of evidence indicating that it makes us outright worse at our jobs as well. Cognitive ability and focus suffer, judgment is
impaired and mistakes become more frequent.1 This principle of diminishing returns is precisely why the 40-hour work week took hold in the first place. When the labor movement forced a drastic reduction in worker hours during the 19th century, businesses across a range of sectors saw a corresponding increase in overall productivity and profitability.2 That spike in performance was coming from factory employees and other manual laborers—the negative impacts of long hours are even more pronounced for today’s knowledge workers..