A comparison of prospective and retrospective assessments of sleep

The main purpose of this study was to evaluate the correlations between retrospective and prospective assessments of sleep. Subjective reports of sleep characteristics and sleep quality were obtained from 146 young (20-40 years, average age 29.15) healthy men (n = 43), nonpregnant (n = 70) and pregnant women (n = 33). Three types of subjective sleep reports were obtained: (1) general estimates of sleep habits (retrospective measures); (2) sleep logs completed upon awakening on three successive workdays (prospective measures); and (3) general sleep complaints. Men showed the greatest stability in the sleep log reports, followed by nonpregnant women, with pregnant women showing the least stability. Significant positive correlations between prospective (log reported) and retrospective (general estimates) sleep measures were found only for men. However, for measures of sleep quality, such as feelings of fatigue upon awakening, women showed greater agreement between their general estimates and three nightly reports. The limitations of using retrospective estimates in sleep surveys are discussed.