ORIGINAL ARTICLE Measuring sleep habits using the Sleep Timing Questionnaire: A validation study for school-age children Rebecca B TREMAINE, Jillian DORRIAN and Sarah BLUNDEN Centre for Sleep Research, Adelaide, South Australia, Australia Abstract In 2003 Monk and colleagues published a single-administration replacement for a standard sleep diary, the Sleep Timing Questionnaire (STQ). Reliable and valid for adult participants, it offers advantages over existing methodologies in cost and convenience. It takes approximately 10 min to complete but can yield information equivalent to a week of actigraphy, or a 2-week sleep diary. This study sought to validate the STQ for school-age children. Sixty-five children (20 boys, 45 girls), aged 11–16 years participated in this study. The participants wore wrist actigraphs, completed a 1-week sleep diary and the STQ. Analyses tested convergent validity between the STQ and actigraphy, and the STQ and sleep diaries. Correlations between STQ and actigraphy (r = 0.45–0.76, P < 0.001), and STQ and sleep diaries (r = 0.42–0.86, P < 0.001), were positive and significant for sleep onset and wake times. Correlations between STQ and actigraphy for sleep latency and wake after sleep onset (WASO) were very low (r < 0.10). In contrast, sleep latency was moderately and significantly correlated between STQ and sleep diary (r = 0.42, P < 0.001), and the correlation for WASO was high and significant (r = 0.74, P < 0.001). Differences between the STQ and sleep diary were within acceptable limits for all sleep parameters, and the differences between STQ and actigraphy were acceptable for sleep onset and school day wake time. The STQ may be a valid indicator of sleep onset and wake time in school-age children. It can also produce measures of sleep latency and WASO with comparable accuracy to a standard sleep diary. Key words: actigraphy, children, sleep, sleep diary. INTRODUCTION In 2003 Monk and colleagues 1 published a single- administration self-report instrument to be used in place of a standard sleep diary, particularly when time or circumstance does not permit the completion of a multi- day sleep diary. This instrument, the Sleep Timing Questionnaire (STQ), was shown to be a reliable and valid measure of sleep parameters (bed time, wake time, sleep latency, and wake after sleep onset), correlating highly and significantly with both a traditional 2-week Sleep Diary (rho = 0.84–0.86), and wrist actigraphy (r = 0.59–0.77). To date, the STQ has been used to measure adult sleep, 2–4 but has yet to be validated for children or adolescents. This is surprising, given that the STQ is able to quantify sleep parameters with accuracy compa- rable to a sleep diary, yet without the level of adherence needed to maintain a daily sleep diary for 1–2 weeks. This is promising, as researchers have noted shortcom- ings of sleep diaries. 5–8 Commitment and compliance with the instruction of filling in a diary every day can prove difficult or unsustainable. 9–11 In addition, several studies of children’s sleep have relied on parental Correspondence: Ms Rebecca Tremaine, Centre for Sleep Research, GPO Box 2471, Adelaide, SA 5001, Australia. Email: Rebecca.Tremaine@unisa.edu.au Accepted for publication 12 May 2010. Sleep and Biological Rhythms 2010; 8: 194–202 doi:10.1111/j.1479-8425.2010.00446.x 194 © 2010 The Authors Journal compilation © 2010 Japanese Society of Sleep Research