Why are there more accidents on Mondays?

Jan 29, 2020

Previous research has found there are more workers’ compensation claims for injuries on Mondays than on any other day of the week. This is often called the “Monday Effect”.

New research published by Motu Economic and Public Policy Research, by Michelle Poland, Isabelle Sin and Steven Stillman has found that the Monday Effect in Aotearoa New Zealand is lower in comparison with countries that don’t have comprehensive injury insurance cover.

If injuries were spread evenly across the work week, then 20 percent of weekday work-based injuries would occur on Monday.

“In New Zealand, nearly 22 percent of serious weekday work injuries occur on Mondays. This is above the 20 percent we’d expect, but lower than in Ontario and Minnesota, where 25 percent and 23 percent of claims respectively occur on Mondays,” said Dr Michelle Poland of WorkSafe New Zealand and the lead author of the paper.

Internationally, the Monday Effect has been blamed on individuals falsely claiming injuries that happened over the weekend instead occurred on Monday at work in order to access workers’ compensation benefits.

“New Zealand’s ACC scheme means workers receive compensation regardless of whether their injury occurred at work, meaning there is no incentive for them to make such false claims. Our finding that there is still a Monday Effect in New Zealand, though it is smaller than in other jurisdictions, suggests fraudulent claims, while relevant, are not the full story,” said Dr Poland.

The study found work injuries that occur on a Monday are less severe than injuries on other weekdays, as measured by compensation for lost work time.

Strains and sprains at work are especially likely to occur on a Monday, but workers also experience a disproportionate number of non-work sprains and strains on Mondays, suggesting the Monday Effect is not limited to the workplace.

“The size of the Monday Effect for sprains and strains is slightly larger, with 22.3 percent of weekday work lost-time claims for sprains and strains occurring on a Monday,” said Dr Poland.

The research also found the proportion of weekly work claims starts high on a Monday and decreases steadily through the week, with the fewest claims on a Friday.

“Our findings suggest the Monday Effect is caused by workers being either fatigued from weekend activities or having lower pain thresholds earlier in the week,” said Dr Poland.

The researchers used data from the Integrated Data Infrastructure (IDI), an individual-level longitudinal data set managed by Statistics New Zealand that links individuals from numerous administrative and survey data sources. The main IDI data used here is accepted accident compensation claims between January 2001 and July 2018.

The Motu Working Paper, “Why are there more accidents on Mondays? Economic incentives, ergonomics or externalities” by Michelle Poland, Isabelle Sin and Steven Stillman and funded by WorkSafe, the University of Otago and the Marsden Fund, is available at the Motu website.