CNN is reporting that a woman 41 years old has a 51% higher chance of having a child with autism than a woman of 25. This is a very scary statistic unless you put some context to it — and CNN didn’t do a very good job of it. Nowhere in the segment did they say what the statistics are at 25 — but MedTV says that the figure is 1 in 166 to 1 in 500. So if you use a rough median figure of 1 in 300 then a 51% increase in likelihood would mean it goes from 1 in 300 to 1.5 in 300. But if you put out a segment as “news” that there’s a new report that a 41 year old woman faces a 1.5 in 300 chance of having an autistic child, while a 25 year old has a 1 in 300 chance — no one would pay attention. Now … quickly here, I don’t want to say the report is not significant. But you see this kind of statistic all the time in reporting of medical studies and almost never do you see context being provided.
