Gifted Issues Discussion homepage Forums Identification, Testing & Assessment Evidence for unreliable scores from young kids

if there are factors that would tend to make early high scores overestimates, I would say that they would almost certainly be found in the "crystallized knowledge" areas of the tests, such as vocabulary, where early environmental enrichment or deprivation could make a huge difference in test performance, giving very young children with relatively enriched environments an apparent "edge" that might not be maintained once children from relatively deprived environments entered school and, hopefully, had more exposure to opportunities to acquire the same level of knowledge.

That's pretty much the way it has been explained to me as well. Vocabulary, for instance: just knowing a few "hard" words will significantly up your vocab portion of the VCI (on the WISC) at a young age b/c there is more head room. If you know more harder words b/c of an enriched environment (or fewer due to a deprived environment), that will make a more significant difference in your IQ score at a young age than it will later.

FWIW, my dd's IQ score on the WISC dropped from the 99.9th at seven to 97th at eight. I don't know that I'm sure either IQ score is correct for her b/c she has ADD and significant anxiety, but I also don't have any data that supports either score as absolutely accurate. Her WIAT scores from the time of the second WISC testing fall closer to the first IQ number but other achievement scores fluctuate wildly.

My other dd has taken multiple above level tests that pretty consistently point to her ability scores falling somewhat above the 99th percentile, but not at the 99.9th. Her IQ at 7 was just into the 99th if we add extended norms. Given all of the other data that supports that and continues to support that even as she nears her teens, I'd have no qualms about saying that her IQ was not an overestimate and was possibly a slight underestimate. My youngest I am now comfortable saying is gifted and maybe HG in some areas (she had one subtest on the WISC that was at the 99.7th and still the 99th with the second testing), but I'm not sold on saying that the highest number ever obtained is the most accurate either.

In quickly looking over the article that I posted on the other thread, it does seem to have some studies of actual IQ tests as well and how one high scores doesn't necessarily indicate that the child will score as highly on a different IQ test or on a second testing of the same test. Here it is again: http://faculty.education.uiowa.edu/dlohman/pdf/Gifted_Today.pdf

The psychologist who tested my son said that it is easier to score very high on tests when the child is younger, rather than older. They only need a few more right answers to score very high.
For example, some of the tests may test reading or pre-reading. If the child is an early reader, they will score very high on that part. However, other children later on may catch up as they also read, etc.
The discussion reminds me of my friend who was so proud that her son walked early. He walked at 9 months. All 3 of her kids walked at 9 months. Great! However, now that the kids are older, although they are doing well, etc., it's not like the kids have gone onto the Olympics!

I don't think so, if I understand correctly what you're asking. But it is all a bit delicate because we have Bayesian reasoning going on under the hood here! Here's an example, with fictional numbers, to show what I was getting at. Consider three situations.

(a) A school gets AvTester to test all 100 pupils. Of all the children AvTester tests, under 1% turn out to have IQs over 150. Jo scores 155.

(b) A school for the gifted gets GTester to test all its 100 pupils. Of all the children GTester tests, 5% turn out to have IQs over 150. Jim scores 155.

(c) Jane is taken to PGTester for testing because she is strongly suspected to be PG. Of all the children PGTester tests (she only does testing on children referred like that), 50% turn out to have IQs over 150. Jane scores 155.

Next year Jo, Jim and Jane are all retested by the same tester. Who if anyone will score over 150? We don't know; but the probability that the child will score over 150, given the information here, is NOT the same for all the children. Jane is far more likely to than Jo. Why? At bottom because the IQ score is not the only information about Jane - we also have the factors that led to her being tested in the first place, and this still matters. It has the effect of making Jane's high score less likely to be any kind of fluke than Jo's is. It's nothing, or not much, to do with being able to guess answers or not; it's to do with there being any uncertainty in the score from any cause. Happening to be asked a question you know the answer to, or happening to be in a good mood that day, or even the tester happening to make a mistake in your favour, or anything, will do.

Notice that the effect of this is that AvTester will see a strong regression to the mean effect, and will perceive that high scores in children this age are relatively unstable, compared with PGTester who will see a weaker regression to the mean effect (NB the mean that matters to her is the mean of the scores *she* sees) and will perceive that high scores in children this age are relatively stable. They're both right, for the populations they test.

What's true for one's own child? There probability gets tricky - you can quite legitimately get very different answers, depending on what population you decide to consider your child as a member of. I hate probability :-)

If you're confused by this you're not alone. It's the same problem as when doctors have to take into account the prevalence of a disorder as well as the test results in estimating the probability that someone with a positive test for a disorder actually has the disorder. They are notoriously bad at doing this. (The moral is, if you ever get a positive result on a screening test, talk to a statistician as well as to your GP :-)

Great post, ColinsMum.

I think aculady's point about crystallized intelligence is a good one, too. The effects of testing assumptions, made when crafting a test for a wide range, must be very different for young kids. For me, it goes back to my distrust of relying on any sort of early milestones as a hard predictor of intelligence levels or future performance, although I think a child who hits milestones early under her own steam will be more likely to be on her way to genius.

Ahhhh... now I have the puzzle piece, thank you ColinsMum A great explanation.

What you said too, aculday, is very interesting. DD had lower scores in a couple of her verbal subtests (because of test fatigue according to the tester). When we were showing her results to a GT coordinator at a school we're considering she made the comment that the verbal stuff 'can be taught anyway'. I thought this was curious as I had never heard this mentioned before. Perhaps that's what she meant - that it's crystallised knowledge.

Thanks all!

Thank you, ColinsMum for such a clear explanation of a tricky topic. That information is really helpful.

Indeed, thankyou! That really helps.

What I have experienced is that IQ scores do change if children are tested from a very young age. I have a friend with three very smart children. They walked, spoke, and acted pretty average throughout babyhood. Beginning at age two, she began teaching her children how to read, count, etc. Beginning with the oldest, his IQ was tested at age 5, where he tested at 140. By five his math and reading ability were at a second grade level. He began regular school, because the gifted program began at grade three. When he was tested at age 8, His IQ was only 116, which did not allow him to qualify for the gifted program. Due to the fact that she maintained him advanced academically by teaching him at home in addition to school, his achievement scores were at the 99th percentile, so she was able to advocate for her son to the point were an exception was made and he was accepted into the gifted program.

The next child, began a stronger regimen of academics at two, and tested at 140 at four. With these numbers, my friend placed her daughter in a private kindergarten (since public school wouldn't accept her at 4). At five she placed her daughter in first grade in public school. When the child was eight and tested for the gifted program, her IQ was 110. Due to the fact that she was advanced academically, 99% achievement scores, etc. She was allowed in the gifted program.

For the last child, she wasn't even tested. She placed her in private kindergarten at 3 1/2, where she did k, 1st grade, then placed her in public school at age 5, with a grade skip (grade 1 again for the child), and now the child is happily placed in the gifted program, with testing waived.

My point is that the kids tested so highly at a young age because they had been taught what they would be tested in, and later received the enrichment of gifted children, which has resulted in very high achievement (so far, the oldest is in college).

IQ numbers can be greatly affected if a child is an early reader, and some may argue that early readers have a high IQ, but coincidentally, almost everyone I know (30+ kids) is reading by age 4. I don't think they're all gifted, but I think its the academic achievement culture that I am around with. I'm pretty sure that if all these kids were given IQ tests they would all test highly gifted and above, yet I don't believe they all are. What are the odds that so many gifted kids would be concentrated in an area/ethnic group?

Anyway, if some of these kids are not placed in the gifted program, and some are, in the long run they will have very different achievement, but all these kids IQ's probably hover around 115.

In my experience, I'm actually uncomfortable with having my children's IQ tested, since my first child did test 145 at age 4, when he attended a preschool for gifted children, but later tested 130 at age 7. I believe his high score was due to his early reading ability, love of puzzles and advanced math skills. With my other children I happen to homeschool, so there's no need for IQ testing.