Database: The Achievement Paradox
By Jim Hull
Over the past several decades, trillions of dollars have been invested to improve our public schools. Critics, however, claim that such investments have been for naught, that there is little evidence our public schools have made any significant improvements.
Many point to results from the National Assessment of Education Progress (NAEP) to show that our nation’s high school students are learning at about the same level now as high school students did nearly 40 years ago. A frequently cited example is that, since the mid-1970s, our nation’s 17-year-olds have only improved their performance by six points in math and by just two points in reading.
When you consider that a good rule of thumb in NAEP is that every 10 points equates to roughly a year’s worth of learning, these results could show our current students are leaving high school only slightly more knowledgeable than high school students 40 years ago.
But do these scores tell the full story?
Numbers don’t lie, but they don’t always tell the whole truth. So let’s take a deeper look into the NAEP data as well as at other student outcomes over the past four decades to determine if critics are right that our schools have failed to improve after nearly 40 years.
Achievement gains by high school minority students
Although the overall averages paint a picture of lethargic improvement over the past 40 years on NAEP, a closer look actually tells a much different story. While a six-point gain in overall math scores between 1978 and 2012 is nothing to write home about, a 20-point improvement for our nation’s black 17-year-olds and one of 18 points for same-aged Hispanics are worth celebrating. Not to mention that white 17-year-olds also made significant improvements during this time period.
Similar results were found on NAEP’s reading assessment, which showed that black students made a whopping 28-point gain between 1975 and 2012, while Hispanic students made a 21-point gain.
How could all of these groups make significant improvements while overall gains were mediocre? The answer: Simpson’s Paradox. This statistical phenomenon occurs when the trends in subgroups disappear once the group results are combined.
The paradox applies here because, when you look at the NAEP results by racial subgroups, you see that each racial group made much larger gains between the 1970s and today than the overall average indicated. This is due to the fact that the demographics in our nation’s schools have shifted dramatically over the past 40 years.
In 1975, 84 percent of NAEP 17-year-old test-takers were white, while black and Hispanic students made up just 14 percent of test-takers. By 2012, the percent of white test-takers dropped to just 56 percent, while black and Hispanic students now comprise 36 percent of NAEP test-takers.
Even though black and Hispanic students have made tremendous gains, gaps between them and their white peers still exist, so their greater share of test-takers suppresses NAEP’s overall average scores. Yet, the results clearly show that black and Hispanic students are achieving at greater levels than ever before, while white students have made significant gains as well.
Progress in math and reading levels is not limited to our 17-year-old minority students. Our nation’s 13- and 9-year-olds have made significant gains as well, especially in math.
Overall, our nation’s 13-year-olds saw a 21-point jump in math scores between 1978 and 2012. That impressive improvement pales in comparison to the 35-point and 33-point gains made by our black and Hispanic students, respectively.
Similarly impressive gains were made by our nation’s 9-year-olds. Overall, they are now acquiring about 2.5 more years of learning than in 1978, with black and Hispanic students acquiring more than three years' worth of learning. These are tremendous gains by any standard.
Beyond NAEP scores
These gains were not isolated to national assessments. On multiple international assessments, U.S. students have made dramatic gains as well. On the Trends in International Math and Science Study (TIMSS), U.S. math scores improved by 23 points at the fourth-grade level between 1995 and 2011.
Similar improvements were made at the eighth-grade level, with U.S. students improving by 18 points. Such gains were among the largest made by participating countries during that time period.
Gains on international assessments weren’t limited to math, either. In reading, U.S. fourth-graders improved their performance by 14 points between 2001 and 2011 on the Progress in International Reading Literacy Study (PIRLS). In TIMSS science, U.S. eighth-graders saw a 12-point gain in their performance between 1995 and 2011.
Gains in both subjects were among the top in the world as well, although they weren’t as dramatic as the overall results from the long-term NAEP.
Graduating more students
Student achievement measures are just one way to evaluate the performance of high school students. Graduation rates are another indicator of progress.
According to the U.S. Census Bureau’s Current Population Survey, the dropout rate was nearly cut in half between 1975 and 2012, falling from 5.8 percent to 3.2 percent.
While graduation rates remained relatively stagnant between 1970 and 2000, they have steadily increased since then. In fact, between 2000 and 2010 -- the most current year available -- the overall on-time graduation rate has increased from 67 percent to 75 percent.
Minority students made even greater gains during this period. In 2010, 62 percent of black students graduated high school within four years, up from just under 50 percent a decade earlier. Meanwhile, Hispanic students made even greater gains over the past 10 years. In 2010, 68 percent of Hispanic students graduated on time, compared to just over 50 percent in 2000.
Keeping the momentum going
The evidence clearly shows our public schools are indeed making significant progress. More students than ever are graduating high school on time, even as our public schools are educating a more diverse student body. Moreover, many are acquiring the equivalent of two to three more years of learning over their peers of a couple decades ago. Such progress should not be dismissed.
Yet, these gains are not enough. Too many of our students -- especially minority students -- are not receiving the knowledge and skills they need to succeed in life after high school. We all must work together to improve these gains by identifying and expanding upon what works.
Jim Hull (email@example.com) is the senior policy analyst at NSBA’s Center for Public Education (CPE).
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