Anonymous wrote:I feel like the adhd studies are making my head hurt. I think the younger kids are being over diagnosed and the older kids are being under diagnosed.
And I don’t understand the Finnish or Danish studies saying allowing liberal redshirting decreases the # of adhd diagnoses. Doesn’t someone still have to be the youngest? And won’t those kids still be at risk for adhd diagnosis? Or at least in the way the system is set up in the US without universal preschool or other school options for every single kid who is “not ready”?
There's not a lot of rationality in DCUM redshirting threads, but I'll try to answer this seriously, as somebody who has closely read these studies, and has also read many of the available studies on redshirting (such as they are). I also have graduate-level statistics training and a graduate engineering degree, so I'm reasonably well-trained in reading academic studies.
The people who are saying that the Danish ADHD study justifies redshirting are incorrect. That study does not do that, any more than the other ADHD studies are an argument for or against redshirting. However, that study is interesting in that it's one of the few large population cohort studies that did
not find a relative age impact concerning ADHD diagnosis and/or medication prescription. This is interesting, because the link between relative age and ADHD diagnosis and/or medication prescription has been repeated across several other populations (Canada, US, Iceland, Portugal, etc.). These are generally studies across large cohorts and are for the most part statistically sound. The Danish study, for instance, covered nearly 1 million children for more than a decade.
The reason that the Danish study did not replicate the results across other populations is not known, but the researchers themselves, in their paper, posited two reasons: 1) That Danish schools have a high proportion of relatively young children with delayed school entry and 2) Denmark has relatively low prescribing rates of medication for ADHD to children. To quote their conclusion exactly:
In conclusion, we found that in most recent years the use of medication for ADHD in Denmark is not particularly affected by children's relative age in class. This may be related to the relatively low use of ADHD medication the country and the highly prevailing custom of delaying school entry for relatively young children.
You're right that somebody has to be the youngest, but what the researchers are positing here isn't about whether somebody is the youngest, it's whether allowing a high proportion of delayed entry has an ameliorating effect on later ADHD diagnosis. By implication, Danish schools tend to have broader age ranges in classrooms, and don't have rigid cutoff dates for entry.
The actual study is here if you want to read it, and some of the other studies are linked from this one:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4277337/
FWIW, I have never read any statistically valid studies that show documented significant harm or long-term significant benefit from redshirting, but it's possible they're out there. I have read a lot of these studies and my conclusion is that the effect from redshirting largely seems to be neutral overall, and is also statistically fairly rare. In general I see nothing (no academic research, at least) to remotely validate the enormous amount of frothing and angst about the topic on DCUM. There is nothing that I've seen that solidly links redshirting to all of the outcomes DCUM posters claim will result one way or the other (positive or negative). Personally I have concluded that worry about redshirting is a stand-in for significant social anxiety, but I have no study to back that up, of course! I don't expect any amount of rational discussion will actually change minds because this isn't a discussion based in reason, for the most part.