Table 2

Description of software-modified phone (SMP) users and calls recorded by the SMPs by study centre

Study centre	Dates of SMP use	No of users	No of calls	No of operators	No of users per operator	No of days of SMP use		No of calls per day	Call duration (minutes)
Study centre	Dates of SMP use	No of users	No of calls	No of operators	Min–max	Mean	Min–max	Mean	Mean
Australia	Nov 03–Jun 04	48	6782	1	48	32.8	17–49	4.5	1.71
Canada	Jan–Jul 05	37	3395	2	13–24	31.8	12–48	3.2	2.08
Denmark	Aug–Oct 03	46	3458	5	2–16	29.1	12–41	2.5	1.80
Finland	Feb–Mar 02	46	4581	4	1–29	27.2	11–38	3.9	2.80
France	Jan–May 01	24	3796	3	3–11	25.4	13–39	6.7	1.88
Germany	Nov–Dec 01	49	3023	2	22–27	25.8	8–42	2.7	1.51
Israel	Aug–Dec 02	41	15058	1	41	34.2	9–50	10.9	1.84
Italy	Feb–Mar 03	53	8049	3	16–20	27.6	19–33	5.4	1.67
New Zealand	Nov 03–Mar 04	27	2466	1	27	37.3	22–72	2.5	1.61
Norway	Sept–Nov 04	48	3946	3	2–24	31.3	14–52	2.7	2.42
Sweden	Apr–May 03	46	5461	5	1–24	27.3	8–42	4.5	1.78
UK North 1*	Feb–Mar 01	17	607	1	17	20.3	9–32	1.6	2.45
UK North 2	Apr–Jul 03	34	2529	5	3–14	27.0	10–35	2.9	2.17
Total		516	63151	36	1–48	29.3	8–72	4.2	1.96

*In the 2001 study in the UK, problems with the phones’ software led to part of the collected data being lost, resulting in few included subjects; the study was therefore repeated in 2003 with a different set of volunteers.