Here are some charts from Gersten, R., Becker, W., Heiry, T., & White. (1984). Entry IQ and yearly academic growth in children in Direct Instruction programs: A longitudinal study of low SES children
. Educational Evaluation and Policy Analysis
, 6(2), 109-121. that show the gains made by the low-SES DI students in Project Follow Through for a range of IQ blocks from under 71 (2 sd below the mean) to above 130 (2 sd above the mean).
There are six IQ blocks shown on the chart. From left to right:Block One:
IQ below 71Block Two:
IQ between 71 and 90Block Three:
IQ between 91 and 100Block Four:
IQ between 101 and 110Block Five:
IQ between 111 and 130Block Six:
IQ above 130
For each IQ block the mean standard score has been graphed at the end of grades 1, 2, and 3.
There are arrows (<, <<, <<<) along the Y axis (mean standard score) that show the national median for each grade. I've (helpfully) drawn a blue line at the third grade national mean, as you can see, only the kids in blocks with IQs above 100 are performing above about the national median for math and only those above 110 for reading. (The blue line only has meaning with respect to the third grade scores (the top point). You could draw horizontal lines from the double arrow (second grade) and compare it to the middle point and from the single arrow and compare it to the bottom point.)
Click on each chart to enlarge.
This chart is for total reading for the Metropolitan Achievement Test.
This chart is for total math for the MAT.
Here is Becker's interpretation of the charts:
The data showed almost no contribution to "learning rate" (pretest to posttest gains) for IQ. If IQ were correlated with gains, lower-IQ children would make smaller gains and higher IQ children would make larger gains. This does not happen for Reading on the Wide Range Achievement Test (decoding) [Ed: Not shown.] or comprehension on the MAT, there is no IQ effect gains from the end of grade one to the end of grade two (most of the gains are about equal), but there is an effect for the gain from the end of grade two to the end of grade three. I believe this effect is due to the fact that the end of third grade test for Reading Comprehension on the Metropolitan uses an uncontrolled, adult-level vocabulary (as found in fourth grade texts). Since vocabulary instruction in school does not progress gradually to the adult level (but jumps from a carefully controlled vocabulary to an adult vocabulary after third grade), the test at this level is now measuring something not taught in school. Thus, students who score higher on a test of verbal skills (IQ) do better on a test of verbal skills (Reading Comprehension) when the content was not systematically taught in school. (A caution: The data may have imposed a ceiling effect on the brighter students; the program stressed preventing failures and thus teachers may have given more effort to teaching lower performers. Even if this is the case, however, the data are noteworthy in showing what can be done "gainwise" for lower-IQ children.)
Here is my observation. I understand Becker's comparable gains argument, but look at the mean percentile ranks for each IQ block:Math End of Third GradeBlock One
(IQ below 71): 24thBlock Two
(IQ between 71 and 90): 39thBlock Three
(IQ between 91 and 100): 47thBlock Four
(IQ between 101 and 110): 61stBlock Five
(IQ between 111 and 130): 69thBlock Six
(IQ above 130): 88thReading End of Third GradeBlock One
(IQ below 71): 11thBlock Two
(IQ between 71 and 90): 29thBlock Three
(IQ between 91 and 100): 34thBlock Four
(IQ between 101 and 110): 44thBlock Five
(IQ between 111 and 130): 58thBlock Six
(IQ above 130): 81st
Also notice the gradual slippage from first to third grades in Reading even for the smartest kids. There is no slippage in math. Interesting.
I don't see how the lower IQ kids are going to be able to learn in a regular classroom given these percentiles. That would seem to foreclose a college education for these students and probably an academic high school education. Am I wrong?
And for the Broader, Bolder crowd, given that many low-SES students have lower IQs and that SES inerventions have not been able to to show a significant effect on IQ past about third grade, how exactly are your proposed SES interventions going to get around this IQ conundrum. Look the high-IQ, low-SES kids are performing well. The low-IQ ones aren't. I'd like to hear a rational argument that makes sense of this.