Table 2.
(Mixed multilevel) regression-based pre, post, and FU estimated means and Cohen's d effect sizes*a
| Measures | Pre, M (s.e.) | Post, M (s.e.) | FU 1 M (s.d.) | FU 2 M (s.d.) | Within Cohen's d pre v. post | Between Cohen's d pre v. post | Cohen's d pre v. FU 3 months | Cohen's d pre v. FU 6 months |
|---|---|---|---|---|---|---|---|---|
| Questionnaires | ||||||||
| PHQ-WS i-Sleep | 7.03 (0.48) | 3.07 (0.44) | 2.86 (2.46) | 3.61 (3.41) | −1.07 | −0.76 | −1.12 | −0.92 |
| PHQ-WS SDiary | 6.70 (0.41) | 5.55 (0.58) | −0.31 | |||||
| PHQ-9 i-Sleep | 9.94 (0.50) | 4.41 (0.55) | 4.00 (2.99) | 5.00 (3.89) | −1.43 | −1.05 | −1.54 | −1.28 |
| PHQ-9 SDiary | 9.35 (0.45) | 7.88 (0.66) | −0.38 | |||||
| ISI i-Sleep | 19.63 (0.49) | 9.57 (0.79) | 9.17 (5.66) | 12.03 (6.64) | −2.90 | −2.36 | −3.01 | −2.19 |
| ISI SDiary | 20.00 (0.48) | 18.14(0.76) | −0.54 | |||||
| FSS i-Sleep | 42.97 (1.26) | 39.54 (1.37) | 34.14 (10.63) | 36.52 (10.23) | −0.36 | −0.23 | −0.92 | −0.67 |
| FSS SDiary | 43.96 (1.21) | 42.70 (1.33) | −0.13 | |||||
| HADS i-Sleep | 7.78 (0.30) | 6.21 (0.50) | 5.31 (2.77) | 6.28 (4.12) | −0.52 | −0.63 | −0.81 | −0.49 |
| HADS SDiary | 7.73 (0.36) | 8.05 (0.54) | 0.09 | |||||
| DC i-Sleep | 15.79 (0.34) | 11.54 (0.59) | 9.03 (4.27) | 10.86 (3.67) | −1.40 | −1.12 | −2.23 | −1.62 |
| DC SDiary | 15.08 (0.33) | 14.22 (0.46) | −0.28 | |||||
| PTQ i-Sleep | 33.89 (1.40) | 24.58 (1.87) | 23.83 (12.48) | 27.36 (14.60) | −0.81 | −0.62 | −0.87 | −0.56 |
| PTQ SDiary | 30.81 (1.48) | 28.63 (1.48) | −0.19 | |||||
| Diary variables | ||||||||
| SE i-Sleep | 68.18 (0.92) | 82.44 (1.56) | 82.60 (7.49) | 79.00 (8.87) | 1.19 | 0.67 | 1.20 | 0.90 |
| SE SDiary | 69.86 (0.94) | 76.13 (1.58) | 0.52 | |||||
| TST i-Sleep | 357.32 (8.30) | 380.95 (7.87) | 344.87 (66.82) | 379.83 (45.42) | 0.36 | −0.05 | −0.19 | 0.35 |
| TST SDiary | 339.79 (9.58) | 359.96 (7.81) | 0.31 | |||||
| WASO i-Sleep | 83.51 (5.86) | 35.42 (3.58) | 49.95 (32.50) | 53.80 (34.73) | −0.91 | −0.60 | −0.63 | −0.56 |
| WASO SDiary | 81.98 (5.54) | 65.78 (5.75) | −0.31 | |||||
| SOL i-Sleep | 66.16 (6.40) | 32.66 (4.93) | 25.89 (15.72) | 36.19 (29.17) | −0.74 | −0.69 | −0.89 | −0.66 |
| SOL SDiary | 55.53 (5.85) | 53.45 (6.90) | −0.05 | |||||
| Mood i-Sleep | 5.71 (0.13) | 6.12 (0.17) | 7.04 (0.62) | 7.04 (0.54) | 0.39 | 0.68 | 1.27 | 1.27 |
| Mood SDiary | 5.62 (0.12) | 5.32 (0.16) | −0.29 |
*A Cohen's d is commonly considered to be either small (i.e. <0.20), moderate (around 0.50) or large (0.80 and over; Cohen, 1988).
DC, daytime consequences; FU, follow-up; FSS, Fatigue Severity Scale; HADS-A, Hospital Anxiety and Depression Scale-anxiety subscale; I, i-Sleep treatment condition; ISI, Insomnia Severity Index; PHQ-9, Patient Health Questionnaire-9; PHQ-WS, Patient Health Questionnaire without Sleep item; PTQ, Perseverative Thinking Questionnaire; SE, Sleep Efficiency; SDiary, sleep diary condition; SOL, Sleep Onset Latency; TST, Total Sleep Time; WASO, Wake After Sleep Onset.
Cohen's d using observed pooled standard deviation at baseline.