To get a sense of the total, complete, and utter mess that is research on the health effects of cell phones, look no further than a study of whether the ubiquitous gadgets raise the risk of brain tumors. “Interphone,” organized by the World Health Organization’s International Agency for Research on Cancer, was the largest (10,751 subjects, ages 30 to 59, in 13 countries), longest (10 years), most expensive (as much as $30 million), and most labor-intensive (48 scientists) study of its kind. That boded well for producing credible conclusions. Instead, Interphone found that using a cell phone decreased the risk of glioma (primary brain cancer) by 19 percent. Even in people who had used cell phones for more than 10 years there was no increased risk of brain tumors, with the exception of those who said they had yakked away for more than 1,640 hours. And the 40 percent increased risk of glioma in this group came with a caveat that is emblematic of this field: this elevated risk, the scientists warned, may be an artifact of “biases and error,” not real. Things got so acrimonious among Interphone scientists that they delayed announcing the results, finally released in May, for four years.