Reuters made a good effort to explain the latest cell phone & cancer study, pointing out the possible limitations in the methodology. Excerpt:
“The Interphone study was an epidemiological case-control study that began with cases — people with brain tumours — and controls — people with no cancer — and asked them to remember how much they had used mobile phones in previous years.
Experts say that case-control studies can be useful in establishing whether a disease is associated with a certain exposure or lifestyle, but they are also susceptible to a number of possible biases that mean results can be unreliable.
One, known as “selection bias” or “participation bias,” comes about because of the voluntary nature of taking part in a study.
Almost 13,000 people were covered in the Interphone study and one potential problem may be that some of those who took part because they have a brain tumour did so because they already believed the disease was caused by using a mobile phone.
This could skew their estimations of how much they used a cell phone and how often they held it on one side of their head where their tumour appeared rather than the other.”