- Cost: You may receive less overtime pay. Discussing your hours with your manager may also take effort.
- In plain language: Records from British munitions factories during the First World War suggest that output increased in proportion to hours up to about 49 hours a week. Beyond that, each additional hour produced less additional output. Output at 70 hours was almost the same as at 56 hours: those extra 14 hours added almost nothing.
- Benefit: In the paper’s fitted models for these historical factory records, output was proportional to working hours below about 49 hours a week. Above that point, output grew more slowly and peaked at approximately 63 hours. Output at 70 hours was little different from output at 56 hours.
- Evidence grade: B, as assigned by the Chinese source; not an independent RecheckNest approval.
- Source: Pencavel (2015). The Productivity of Working Hours. The Economic Journal. https://doi.org/10.1111/ecoj.12166
- Notes: These data concern manual factory work a century ago, mostly performed by women. The threshold may differ for knowledge work; the author notes that it may be higher or lower in other occupations. The useful takeaway is diminishing returns beyond some point, rather than treating 49 hours as a dependable threshold for every job.
Editorial scope note: These hour values are model estimates for the studied workers. The author selected the 49-hour spline knot partly for historical reasons and compared alternatives; it is not a universal work-hour limit. The approximately 63-hour peak describes the main fitted specification, rather than every specification. The working paper also uses 48 hours when discussing occupational generalization; that wording difference is retained in the review record.