Development and validation of the Japanese version of the Bedtime Procrastination Scale (BPS-J)

BMC Psychology

Table 5 Bivariate correlation between the BPS-J and variables

	Full item		Item 2 Eliminated		Item2 & 3 Eliminated
	Spearman's ρ	p	Spearman's ρ	p	Spearman's ρ	p
Brief self-control scale	0.40	< 0.001	0.40	< 0.001	0.41	< 0.001
General procrastination scale	0.49	< 0.001	0.48	< 0.001	0.49	< 0.001
Sleep duration on workdays	- 0.35	< 0.001	- 0.32	< 0.001	- 0.31	< 0.001
Feeling fatigue at daytime	0.33	< 0.001	0.33	< 0.001	0.34	< 0.001
Feeling sleep loss at daytime	0.48	< 0.001	0.48	< 0.001	0.50	< 0.001
Viewing bedtime procrastination as a problem	- 0.02	0.68	0.01	0.68	0.03	0.84
Munich ChronoType Questionnaire
Sleep duration on workdays	- 0.33	< 0.001	- 0.34	< 0.001	- 0.33	< 0.001
Sleep duration on work-free days	- 0.13	0.001	- 0.12	0.004	- 0.10	0.02
Midsleep at workdays	0.40	< 0.001	0.41	< 0.001	0.41	< 0.001
Midsleep at work-free days	0.42	< 0.001	0.43	< 0.001	0.44	< 0.001
Absolute social jetlag	0.21	< 0.001	0.22	< 0.001	0.24	< 0.001
Absolute social jetlag ≥ 120 min	0.13	0.002	0.16	0.007	0.17	0.004
Weekly sleep loss	0.14	< 0.001	0.14	< 0.001	0.16	< 0.001
Working time	0.07	0.07	0.08	0.052	0.07	0.08
Work start time	0.10	0.07	0.07	0.07	0.08	0.08
Work end time	0.11	0.009	0.12	0.004	0.12	0.004

P probability value, Full items the full-item model, Item 2 eliminated the Item 2 eliminated model, Items 2 and 3 eliminated the Items 2 and 3 eliminated model; Bold = p < .05

ISSN: 2050-7283