PSQI largely ignores sleep on work-free days both in the general population and in clinical sleep medicine samples

Introduction: The Pittsburgh Sleep Quality Index (PSQI) is currently the most common measure of sleep quality. Its questions refer to "usual" sleep habits over the past month. However, for long it is known that sleep timing and sleep duration varies significantly between workdays and work-free days. A recently submitted study in the general population used the original and two adapted versions of the PSQI that replaced "usual" by explicitly referring to sleep on work- or work-free days. This study showed, that also sleep quality differs significantly between work- and work-free days.

http://ift.tt/2BZzn6g