On Monday Prof. Douglas Gentile of Iowa State University in conjunction with the National Institute on Media and the Family released the results of a new study which suggested that one in twelve 8-18 year-olds displayed symptoms of video game addiction.
As GamePolitics reported, the methodology behind the ISA/NIMF research was almost immediately called into question by Harvard’s Dr. Cheryl Olson, co-author of Grand Theft Childhood and Oregon psychiatrist Dr. Jerald Block, an expert of the topic of video game addiction.
A report today by ABC News polling director Gary Langer (left) goes a step further, questioning Gentile’s study for its claim of being "nationally representative within 3% [margin of error]."
Writing for his The Numbers blog, Langer explains:
The problem: This study was conducted among members of an opt-in online panel – individuals who sign up to click through questionnaires on the internet in exchange for points redeemable for cash and gifts. There are multiple methodological challenges with these things… but the most basic – and I think least arguable – is that they’re based on a self-selected “convenience sample,” rather than a probability sample. And you need a probability sample to compute sampling error…
This is far from an inconsequential issue. The public discourse is well-informed by quality data; it can be misinformed or even disinformed by other data. It is challenging – but essential – for us to differentiate.
Langer also heard from the study’s author who admitted the mistake in calculating a margin of error:
Prof. Gentile got back to me… He said he was unaware the data in his study came from a convenience sample… and that, relying on his own background in market research, he’d gone ahead and calculated an error margin for it. “I missed that when I was writing this up. That is an error then on my part.”