Table 1 Recalled phone use compared to actual phone use: number of calls.

Country	Subjects (n)	Mean calls/month (n)	Correlation coefficient	Weighted kappa (95% CI)*	Ratio of recalled to actual number of calls
					Geometric mean ratio (95% CI)	95% limits of agreement†	% subjects with ratio 0.5–2
Australia	44	154	0.78	0.59 (0.38–0.80)	1.06 (0.83–1.35)	0.21–5.42	61%
Denmark	44	75	0.50	0.35 (0.16–0.54)	0.80 (0.67–0.96)	0.23–2.75	73%
Finland	77	168	0.62	0.42 (0.27–0.57)	1.07 (0.90–1.27)	0.23–5.06	65%
France	65	135	0.63	0.41 (0.25–0.57)	0.90 (0.72–1.13)	0.14–5.97	59%
Germany	75	54	0.53	0.34 (0.17–0.50)	0.78 (0.60–1.02)	0.08–7.89	45%
Israel	39	351	0.59	0.34 (0.13–0.56)	0.91 (0.66–1.24)	0.12–6.83	54%
Italy	89	156	0.55	0.38 (0.24–0.52)	1.10 (0.89–1.36)	0.15–8.38	58%
New Zealand	19	68	0.79	0.29 (0.02–0.57)	0.42 (0.28–0.64)	0.06–2.77	42%
Norway	45	84	0.51	0.21 (0.06–0.36)	0.45 (0.35–0.59)	0.08–2.62	44%
Sweden	44	139	0.76	0.50 (0.30–0.70)	0.85 (0.64–1.12)	0.13–5.63	64%
UK‐North SMP study	40	78	0.71	0.39 (0.18–0.60)	0.62 (0.47–0.80)	0.11–3.30	53%
UK‐North operator study	91	33	0.44	0.34 (0.20–0.48)	1.61 (1.23–2.10)	0.12–21.82	54%
Total all countries	672		0.69	0.50 (0.44–0.55)	0.92 (0.85–0.99)	0.12–7.85	57%
Excluding countries not using CAPI‡	497		0.70	0.49 (0.43–0.55)	0.86 (0.79–0.94)	0.12–5.98	57%
Excluding UK‐North operator study	581		0.70	0.48 (0.43–0.54)	0.84 (0.78–0.91)	0.13–6.01	57%

*Weighted kappa statistic for quintiles of the distribution of actual number of calls.

†95% limits of agreement: mean plus/minus two standard deviations.¹⁵,¹⁶

‡Sweden and the UK are the excluded countries.

CAPI, computer assisted personal interview.