It's not going to happen. Not anytime soon. Not ever.
To raise the achievement gap, we need to raise the performance of the lower performing groups. (Another way is to drag down the higher performing groups. But that's just silly.)
There exist two schools of thought.
The first school believes that the achievement gap is caused by factors external to schools, such as poverty, racism, discrimination, and the like. The theory goes that if you eliminate or ameliorate these factors, you can raise the performance of the low performing groups up to the level of the higher performing groups. Sounds good in theory, kinda like communism sounded good in theory. In practice, however, results have been elusive and by elusive I mean non-existent. Unfortunately, no amount of wishful thinking in editorial pages seems to be able to get this theory past the the rainbows and magic stage of development. Needless to say, this is the dominant view of most educators.
The other school of thought is that the poor performance of the lower performing groups is the result of inferior instruction. Improve the instruction and performance will also improve. One problem with this school of thought is that improving instruction has also been an elusive task. Most efforts to improve the performance of low performers via improved instruction have failed miserably. You can count the number of successful programs that achieve consistent, reliable, and educationally significant results on your fingers of one hand. You have DI, SfA, and a few others. The "problem" with this improved instruction approach is that improved instruction won't just raise the performance of low performers it will raise performance across the board, so the achievement gap isn't going to be reduced in real terms any time soon. But, don't take my word for it take Zig Engelmann's, the creator of one of the few instructional programs that has gotten positive results:
Following the remodeling [in 1972], we opened a learning center, which was designed to serve hard-to-teach children and school failures. One of the earliest groups, however, was not low, but was composed of six preschoolers whose parents were professionals or professors. One student was Wes' youngest son. We worked with these children as four-year-olds and five-year-olds. They went through the reading and math programs as fast as they could go at mastery, which was frighteningly fast. (There was no need for the language programs because these children were very bright.) Even though they worked for only a little more than an hour a day, they went through all four levels of the programs we had for Follow Through classes. Before they
entered first grade, they performed on the fourth-grade level in both subjects. And they loved school.
We never published anything about the performance of these children, largely because the group had only six children, which meant that experimental purists would "question" the results. (Usually, at least 15 experimental children are needed for establishing outcomes that are recognized as valid.)
Although these children were awesome, their performance showed a critical difference between their potential and that of the at-risk child. When these advantaged children came to the third and fourth levels of the reading program, where the material becomes entrenched in and decorated with sophisticated language, they did not slow down. The profile for the at-risk child is different. Performance slows considerably when they reach the vocabulary-rich transition. They have parallel problems with math when the word problems become more substantive than a few pared-down sentences that present necessary information in a "familiar" format.
... [W]e don't have to worry as much about the performance of higher performers. They will tend to learn from teaching that is hideous, as many programs for the talented and gifted demonstrate. These programs provide instruction that appears to be purposely designed to teach, explain, and develop skills in the most circuitous and confusing manner possible. Certainly it's cruel to subject students of any skill level to such instruction, but in the larger scheme, far less cruel than subjecting at-risk children to certain failure. Although it would have been possible for us to work with both populations, we reconfirmed the decision not to work with higher performers but rather to show the degree to which at-risk children would catch up to higher performers with careful instruction. We figured that teaching higher performers effectively is so easy that in time, those who educate them would learn how to do it effectively. It certainly hasn't happened yet. But we felt that we needed to work with the lower performers simply because it is not easy and teachers don't know how to do it. In fact, we believed that if we didn't do it, it wouldn't happen because nobody in or out of Follow Through (with the exception of the University of Kansas) was close.
This finding was later confirmed in a subsequent study;
To show the degree of acceleration that was possible with students at or above average, Doug Carnine and I did a formal study, which appeared in our 1978 Technical Report to National Follow Through. Thirty children in a Springfield, Oregon elementary school went through our reading program at an accelerated rate. These were not children with extremely high IQs, but all but two met the district’s criteria for "higher performer," which was that they performed at or above the district average when they began the first grade. (The district had no kindergarten.) The two exceptions were low performers who were added because the teacher felt they could benefit from the program. During grades 1 and 2, the children had daily reading lessons of about one-half hour per day and devoted another half-hour to independent work. The teaching was conducted by trainees in our practica. The classroom teacher was a star, but she did very little of the teaching. She made sure, however, that the trainees performed very well.
At the end of their second grade, children read at the middle fourth grade level according to the Stanford Achievement Test. They performed on the fifth-grade level of an oral reading test. The top ten children received a fourth-grade test that measured speed and accuracy. (We could find no test for the second or third grade.) Students performed on the seventh-grade level.
The children were not taught science as a subject, but level 3 of our reading program has stories that are heavy in science content. The class performed at the fourth-grade level in science.
These results shouldn't be surprising to anyone. If the quality of instruction is held constant, smart kids will always learn more and faster than their dull peers. And yet, you can't go a day without reading how the goal of education is to eliminate the achievement gap. The allure of rainbow and lollipop solutions is strong. but, based on the evidence at hand, it's not going to happen. So, get over it.