Statistics reassure us that having a child with a cleft does not mean you’ll have other children with the same condition. In fact, your chances only increase by 2 to 5 percent compared to couples with no cleft-affected children.
What they mean:
The chances that your next child will have cleft palate increases from 0.15% to about 4%. Your odds ratio multiplier is 25.
I didn’t click-through and there might be more context than this, but “chances only increase by 2 to 5 percent” is ambiguous between “percent (as an absolute probability)” and “percent (of the chance it was before)”. I’m not sure if it qualifies as an “irrationality quote”, it’s just unclear and could be confusing, but /u/PhilGoetz’s version is a step up.
(I’d maybe not use “odds ratio multiplier”, because we’re not just concerned about clarity, but clarity to people who might be statistically illiterate)
From the International Craniofacial Institute’s web page on cleft palate.
What they say:
What they mean:
Why should people care about the odds ratio in this case instead of caring about the absolute risk?
It seems to me that if a patient get’s a child with a cleft palate they care about the absolute risk of their next child also getting it.
I didn’t click-through and there might be more context than this, but “chances only increase by 2 to 5 percent” is ambiguous between “percent (as an absolute probability)” and “percent (of the chance it was before)”. I’m not sure if it qualifies as an “irrationality quote”, it’s just unclear and could be confusing, but /u/PhilGoetz’s version is a step up.
(I’d maybe not use “odds ratio multiplier”, because we’re not just concerned about clarity, but clarity to people who might be statistically illiterate)