Table 2. Characteristics of working days, days off, scheduled absences, sickness absence days, length of working hours, shift intensity, recovery, and social aspects of working hours in intervention and control groups in 2012 (for 10 months) preceding the working-hour intervention, and during the intervention year 2013 (for 10 months).

Working days, days off, scheduled and sickness absence days	Intervention group (n=493)					Control group (n=2,303)
	2012		2013			2012		2013
	mean	range	mean	range		mean	range	mean	range
Working d/3-wk period	10.0	0–15	9.6	0–15		10.3	0–16	10.0	0–15
Days off/3-wk period1	5.8	0–13	5.3	0–12		5.8	0–11	5.6	0–10
Scheduled absence d/3-wk period2	6.5	1–11	6.9	1–11		6.3	1–11	6.8	1–11
Sickness absence d/yr3	6.7	0–154	7.0	0–129		11.5	0–275	14.5	0–286
Amount of sickness absence	%		%			%		%
None at all	32		30			24		23
1‒3 d	29		28			23		20
4‒31 d	36		38			43		45
32 d or more	3		4			10		12
Length of working hours
Weekly working hours (h)	33.4	8.0–40.8	33.6	5.3–40.9		34.9	8.0–49.3	34.8	4.0–50.5
% of long (> 40 h) working weeks	24	0–60	25	0–75		26	0–100	27	0–100
% of long (> 48 h) working weeks	4	0–38	5	0–35		5	0–58	5	0–100
Shift length (h)	8.2	5.1–10.5	8.2	4.8–10.5		8.5	5.7–12.4	8.6	4.0–13.1
Shift intensity
Number of consecutive working days	4.7	2.0–7.3	4.8	2.0–7.0		4.7	2.0–7.0	4.7	2.0–6.9
% of long spells of work shifts	3	0–20	4	0–19		4	0–19	4	0–19
Number of consecutive night shifts	3.9	2.0–7.3	4.0	2.0–6.8		4.0	2.0–6.7	4.0	2.0–7.0
% of long spells of consecutive night shifts	4	0–29	4	0–33		4	0–37	4	0–35
Recovery
Time between shifts (h)	15.7	12.4–22.9	15.7	10.5–19.4		15.5	12.0–19.9	15.4	0.5–20.5
% of short shift intervals	18	0–67	18	0–60		21	0–58	21	0–100
% of short recovery periods after last night shift	5	0–100	3	0–100		4	0–100	5	0–100
Social aspects of working hours
% of annual leave days	12	0–57	13	0–82		11	0–44	12	0–94
% of weekend work	38	0–100	37	0–100		43	0–100	42	0–100
% of single days off	18	1–100	19	1–100		18	1–100	18	1–100
Variability of shift starting times	2.7	0–6.2	2.8	0–6.1		3.4	0–6.8	3.3	0–6.5
% of realized shift plans	92	40–100	92	15–100		91	0–100	91	0–100
% of preferred shifts	18	1–100	20	1–100		7	1–100	7	1–100
% of realized shift preferences	7	0–55	8	0–49		3	0–53	3	0–52

¹ Days off are scheduled days off (but not annual leave or anything else) within a three-wk period

² Scheduled absences (sick leave, maternity leave, annual leave etc.) are planned into the scheduling programme for each three-wk period

³ Sickness absence days include all days of absence (sudden or scheduled) due to sickness