> The study itself uses criteria for gender dysphoria that's been outdated for decades.
The study uses the DSM-III and DSM-IV criteria for gender incongruence disorder, or GID, now referred to as gender dysphoria. The sample ranges from 1989 to 2002 and those were the contemporary iterations of the DSM. The DSM-V wasn't published until 2013. At most the criteria is outdated by one decade, not "several decades". Furthermore, the author of the study would later write the criteria for gender dysphoria in the DSM-V. The criteria are not particularly different, and the author of the study I linked has stated in interviews that most of the sample would meet the criteria for gender dysphoria under the DSM-V (which, again, he wrote so this opinion should carry some weight). In short, the idea that if the psychologists had used the DSM-V the results would be substantially different is not likely.
And this isn't just one study that found low rates of persistence:
> In Green (47), the percentage of persisters was 2% (total n = 44; Mean age at follow-up, 19 years; range, 14–24); in Wallien and Cohen-Kettenis (52), the percentage of persisters was 20.3% (total n = 59; Mean age at follow-up, 19.4 years; range, 16–28); and in Steensma et al. (51), the percentage of persisters was 29.1% (total n = 79; Mean age at follow-up, 16.1 years; range, 15–19). Across all studies, the percentage of persisters was 17.4% (total N = 235), with a range from 0 to 29.1%.3
Are all these other studies finding low rates of persistence also tainted in some way?
The study you linked is among a group that were treated with an affirming model of care, where cross sex gender identity is actively encouraged, and a sizeable chunk of the sample were put on puberty blockers. This comports with what I have written: when gender dysphoric children are met with an affirming model of care and given gender affirming care, very few of them desist in their cross-sex gender identity. When they given a neutral, observational model of care not not prescribed puberty blockers, the majority of them desist. The study you linked just reinforces the former but does nothing to disprove the latter.