study, design, methods | negative studies | positive studies |
---|---|---|
Mobile phone use | inadequate: 2-5 min/day | significant: 16-32 min/day |
Latency time | <5% cases with latency ≥10 y | >18% cases with latency ≥10 y |
Cordless phone users | considered unexposed | considered exposed |
Ipsilateral tumour latency | ≥10 y for only 2% cases | ≥10 y for >16% cases |
Head tumours identified | only gliomas, meningiomas, neuromas, parotid tumours | also other head tumours types |
Deceased cases | not included | included: proxy interviews |
Interviews | not blind | always double blind |
Type of interviews | face-to-face | mailed questionnaires |
Time of interviews | cases: during hospitalisation | cases: after hospitalisation |
 | controls: at home | controls: at home |
Exposure assessment | non blind interview | blind questionnaire |
Data processing | not stated (not blind?) | Blind |
Laterality attribution bias | present | Absent |
Delayed interviews | for controls compared to cases | not delayed |
Participation | reduced up to 40% | always near to 90% |
Selection | exposed controls prevail | no selection bias |
Documentation | positive data ignored | no documentation bias |
Funding | co-funded by MP Companies | funded only by Public Bodies |