Table 1

 Recalled phone use compared to actual phone use: number of calls

CountrySubjects (n)Mean calls/month (n)Correlation coefficientWeighted 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
*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.
Australia441540.780.59 (0.38–0.80)1.06 (0.83–1.35)0.21–5.4261%
Denmark44750.500.35 (0.16–0.54)0.80 (0.67–0.96)0.23–2.7573%
Finland771680.620.42 (0.27–0.57)1.07 (0.90–1.27)0.23–5.0665%
France651350.630.41 (0.25–0.57)0.90 (0.72–1.13)0.14–5.9759%
Germany75540.530.34 (0.17–0.50)0.78 (0.60–1.02)0.08–7.8945%
Israel393510.590.34 (0.13–0.56)0.91 (0.66–1.24)0.12–6.8354%
Italy891560.550.38 (0.24–0.52)1.10 (0.89–1.36)0.15–8.3858%
New Zealand19680.790.29 (0.02–0.57)0.42 (0.28–0.64)0.06–2.7742%
Norway45840.510.21 (0.06–0.36)0.45 (0.35–0.59)0.08–2.6244%
Sweden441390.760.50 (0.30–0.70)0.85 (0.64–1.12)0.13–5.6364%
UK-North SMP study40780.710.39 (0.18–0.60)0.62 (0.47–0.80)0.11–3.3053%
UK-North operator study91330.440.34 (0.20–0.48)1.61 (1.23–2.10)0.12–21.8254%
Total all countries6720.690.50 (0.44–0.55)0.92 (0.85–0.99)0.12–7.8557%
Excluding countries not using CAPI‡4970.700.49 (0.43–0.55)0.86 (0.79–0.94)0.12–5.9857%
Excluding UK-North operator study5810.700.48 (0.43–0.54)0.84 (0.78–0.91)0.13–6.0157%