Research suggests that workers with uncertain work schedules tend to have lower levels of happiness.

A research team from Pennsylvania State University and other institutions in the United States has reported that workers whose work hours are not determined until the last minute tend to have lower overall life satisfaction than workers with regular work hours.

Do Unpredictable and Unstable Work Hours Reduce Subjective Wellbeing? | Social Indicators Research | Springer Nature Link
https://link.springer.com/article/10.1007/s11205-026-03853-5

When you don't know your work schedule, your happiness may pay the price
https://www.scienceofmoney.org/when-you-don-t-know-your-work-schedule-your-happiness-may-pay-the-price-652/

Traditional research on work and happiness has primarily focused on long working hours and the discrepancy between desired working hours and actual working hours. This time, a research team led by Ronnie Golden of Pennsylvania State University Abington has focused not only on 'how long you work,' but also on 'whether you can know in advance when you will be working.'

The research team selected 437 to 750 people from respondents of the 'Work Orientations IV' survey module of the International Social Survey Program, which is part of the 2016 U.S. General Social Examination. These respondents worked full-time or part-time, excluding the self-employed and military personnel, depending on the analysis items. The indicator of subjective well-being in overall life was the response to the question, 'Considering your current life as a whole, how would you rate your happiness: 'very happy,' 'quite happy,' or 'not very happy'?'

To capture the predictability of work schedules, the researchers used two questions: how many days in advance participants know their work days and times, and whether their work hours are 'regular,' 'regularly changing,' or 'decided at the last minute.' The research team then analyzed the relationship between work schedule predictability and well-being, subtracting the influence of factors such as age, health status, household income, occupation, previous week's working hours, and who determines work hours.

When the research team compared how work hours were determined, they found that people who reported their daily work hours were 'decided at the last minute' tended to be happier than those who reported their work hours were 'regular.' Furthermore, after subtracting the influence of differences such as age, health status, and household income, the correlation between having work hours decided at the last minute and low happiness was about twice as strong as the correlation between household income and happiness.

On the other hand, no clear difference in happiness levels was found between people whose work hours changed regularly and those whose work hours were regular. The research team believes that the uncertainty of work hours until the last minute, rather than the changes themselves, is more strongly associated with happiness.

However, 38 of the participants in the analysis reported that their daily work hours were 'decided at the last minute.' The tendency for people whose work hours are decided at the last minute to report lower levels of happiness compared to those with regular work hours only became clear after accounting for the influence of differences in household income, so the research team says that this needs to be interpreted carefully.

When the research team compared the timing of work schedule notification, they found that those whose schedules remained unchanged reported the highest levels of happiness, while those who learned of their work schedules two days to a week in advance tended to have lower levels of happiness. On the other hand, those who learned of their work schedules one day in advance or on the day of the work did not show a significantly lower level of happiness. The research team suggested that last-minute notification may be associated with overtime, and that some men may welcome increased working hours, even in unpredictable ways, but they stated that further investigation is needed to confirm this point.

Furthermore, in an additional analysis excluding those who could determine their own working hours, a clear correlation between work schedules and happiness could no longer be found for many indicators. The research team explained that the results could differ depending on whether working hours are determined by the employer or can be adjusted by the worker. Since this study did not track the same individuals over a long period, it cannot be definitively concluded that not knowing working hours until the last minute causes a decrease in happiness.

The research team argues that measures to improve worker well-being should include making working hours and schedules more stable and predictable.