For something at a first grade level, consider, say, spelling bees. I read a lot as a kid, and correspondingly did very well on things like that, but across the hundreds or thousands of words these things go through... well, the people at Scripps aren't just reading lots of books.
It's also been my experience that the people who implicitly understand something tend not to want to bother with recommended prep. That was me for CS courses, some calculus, and english/writing, where I got high grades but often not top of the class. I was on the opposite side for history and statistics (and outscored at least some of the people who are far better at those subjects than I am).
Basically, if you're gifted and already have knowledge of a subject, you probably don't really want to spend lots of time studying it. This leaves you vulnerable to the weird 5% of edge cases you haven't seen before. If you don't know the subject, and have to do a lot of prep, you're going to come across those cases during prep.
RE percentage vs percentile: I think you may be wrong here. Take for example, uni exams. 40% is the pass mark here in old Blighty. The exams are standardised and the 40% threshold is not a percentile. In fact, it makes almost no sense at all to stackrank every cohort of test takers. It wouldn’t be fair at all not comparable over time. I think the parent poster is correct. Doubtless the empirical distribution of real scores are used to decide cutoffs for grades, by 99% in the parents posts very likely refers to a percentage.
If none scores 99% then you just don’t take anyone ... in your method if everyone scored 0% you’d still take a bunch. I don’t think that makes any sense.
> in your method if everyone scored 0% you’d still take a bunch.
Yes, and they will. My understanding is it's still a normal school, just with a special selection of students; what are they going to do, shut down for the year?
https://psycnet.apa.org/record/1984-16352-001
https://psycnet.apa.org/buy/2007-03270-007
https://onlinelibrary.wiley.com/doi/abs/10.1002/1097-4679(19...
> My eyes just rolled looking at that number. That means they only pick 98 and 99 percentiles.
Either one of these is wrong, or they somehow managed to craft a test where the score percentage matches the score percentile, which while possible to engineer is somewhat improbable and also contradicts the next sentence:
> For a first grader to score that high, she needs to answer the exam perfectly.
Irrespective of one’s current grade level, it doesn't require answering an exam perfectly to get a 98%. It might to get a 98 percentile score (depending on what other people taking the score get).
> If you have some statistics training, you'll see this score is like shooting yourself in the foot.
If you have some statistics training you'll recognize the difference between percentages and percentiles and which of the former corresponds to a perfect score.
The test-retest validity of IQ tests (which tests for gifted programs either expressly are or are equivalent to) is such that it's not unreasonable at all to think that people will consistently score at about the same place based on ability over a short time period (over a longer span there'll be some variation) and that being a prepared test taker isn't a particularly significant factor, though anxiety about testing or the particular test could depress scores and soothing that is the main benefit of test prep.
Yes, the levels most districts use a gifted cutoff are very high (usually 97th-99th percentile). Yes, that means very few (1-3%) will make the cut. No, this doesn't mean the people that make the cut are just test-taking prodigies.