Kristian G. AndersenGeverifieerd account

Hmmm, I don't know - I'm a little skeptical. Haven't had time to read in detail and I'm not familiar with most of the tests, however: 1. No control group (not acceptable IMO) 2. They talk about below average (as opposed to normal) all the time. We'd assume ~50% would be < avg!

I agree with you regarding the lack of control group - I found it hard to know what should be considered normal (average...). Still, 31% is alarmingly high.

Agree that control groups are always good - but Bayley scales are regarded as the "gold standard" for neurodevelopment and, as far as I understand, ranges of "normality" have been established in large population-based studies, and validated across settings (including Brazil).

Thanks Isabel, this is helpful - because as I mentioned, I'm not familiar with these tests. However, when they say "below average", do they actually mean "below normal compared to a test validated to a fully matched control group"? If yes, then OK, but otherwise not.

I think that by below average they just mean below the age-standardized mean (which I think is a 100, SD=15). Not sure if the "below average" is meaningful at all.

From the paper: "A Bayley-III score within 1 s.d. above or below the norm of 100 was considered normal...A score of .... 1–2 s.d. below the norm (< 85 to 70) [was considered] moderately below average. A score... 2 s.d. below the norm [was considered] well below average (<70). "

Yeah, I’m not really sure that tells us much? Again, the most critical question here is, what would the distribution look like in a matched control group?