Factors affecting the extent of Monday blues: evidence from a meta-analysis.

A meta-analysis of 34 samples identified a small but reliable "Monday blues" effect (-.08 < or = d < or = -.06) in samples reporting current or real-time moods for each day of the week. However, the size of the effect in samples reporting recalled summaries of moods experienced over the course of a day varied depending on whether the sample involved university students or nonstudents. University students reporting recalled summaries of daily moods showed a large Monday blues effect (d = -.25), whereas married men who were not students reported smaller effects with greater variance (-.19 < or = d <or = -.01). The 34 samples reporting recalled summaries of moods experienced over multiple days produced effects ranging from -.25 to -1.28, but the variance among these samples was too great to estimate an aggregated statistic.