Recall of past use of mobile phone handsets.
Previous studies investigating health effects of mobile phones have based their estimation of exposure on self-reported levels of phone use. This UK validation study assesses the accuracy of reported voice calls made from mobile handsets. Data collected by postal questionnaire from 93 volunteers was compared to records obtained prospectively over 6 months from four network operators. Agreement was measured for outgoing calls using the kappa statistic, log-linear modelling, Spearman correlation coefficient and graphical methods. Agreement for number of calls gained moderate classification (kappa = 0.39) with better agreement for duration (kappa = 0.50). Log-linear modelling produced similar results. The Spearman correlation coefficient was 0.48 for number of calls and 0.60 for duration. Graphical agreement methods demonstrated patterns of over-reporting call numbers (by a factor of 1.7) and duration (by a factor of 2.8). These results suggest that self-reported mobile phone use may not fully represent patterns of actual use. This has implications for calculating exposures from questionnaire data.
Parslow
R C
RC
Paediatric Epidemiology Group, Unit of Epidemiology and Health Services Research, University of Leeds, Leeds, LS2 9LN, UK. r.c.parslow@leeds.ac.uk
Hepworth
S J
SJ
McKinney
P A
PA
D000293:Adolescent; D000328:Adult; D000368:Aged; D040421:Cell Phone; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011846:Radio Waves / Q000009:adverse effects*; D015203:Reproducibility of Results; D012650:Self Disclosure; D012737:Sex Factors; D011795:Surveys and Questionnaires; D013997:Time Factors