Two friends have commented on the tanning bed example in my previous post. In light of their good points, I’ll highlight the example’s weaknesses and add some information to clarify.
1. It reads as an apology or justification of tanning bed use. If you know me, you know that I’ve used tanning beds before so it’s easy for it to appear this way. Perhaps you don’t know me but were tempted to assume the same.
2. The argument might have been more clear if I quantified it. Let’s say 10 minutes in a tanning bed delivers the UV ray equivalent of about 30 minutes of real sun. My point is that 40 minutes per week in a tanning bed is probably equal in cancer risk exposure to 2 hours per week in the real sun. However the sunbed user/cancer link makes it seem like tanning beds cause cancer in some special way.
3. I think a lot of people, perhaps most, assume that tanning beds cause cancer in some special way. I think this based on my own personal experience. If people noticed I was sunburnt, they would typically chuckle or make a comment about needing to use sunblock. If I was tan at a weird time, say day 13 in a row of Georgia summer rain, and I explained that I went to a tanning bed, I might get different reactions. Sometimes they would outright chastise me for it, other times they would passively ask “aren’t those really bad for you?” Other times yet they would say “oh,” and I assume at least some of the “oh”s are in place of a comment about the dangers of indoor tanning. I don’t think tanning beds are good for you, but neither is getting baked by real sun.
4. The example could have been even more illustrious if I pointed out that the demographic who uses tanning beds is the demographic most likely to get skin cancer: fair-skinned people.
5. There’s a general weakness in the example because I’m speculating about something that might or might not be true. This makes it confusing because I’m asking readers to imagine a hypothetical situation while delivering a persuasive argument as to why the hypothetical situation might be real.
6. I thought it was a good example because it has all the components I wanted to include: a clear G (indoor tanners), an elusive X (obsessive tanners), an A caused by erratic behavior, and a familiar correlation that’s often assumed to be causality.
7. A better example might have been divorce rate. “50% of marriages end in divorce.” That well-known statistic is based on the marriage rate being twice the divorce rate. The site below (I’m having hyperlink issues) states that the divorce rate is 41% for marriage #1, 60% for marriage #2, and 73% for marriage #3. So while a young couple getting married may be thinking that there’s a 50% chance they’ll divorce their partner, the truth is those odds are lower. The extremist group—people who get divorced 2 to 7 times—are raising the divorce rate data for everyone.
Thanks DT and MK.