by Jamie Gumbrecht
(CNN) -- Every couple of years, the National Assessment of Educational Progress releases a short-term snapshot of how students fare in science, civics or other subjects.
But it doesn't quite answer the big question: How are students really doing?
That's the job of a report released Thursday, "The Nation's Report Card: Trends in Academic Progress 2012." It's an assessment released every four years that tracks U.S. students' performance in reading and math since the 1970s. The 2012 assessment included more than 50,000 students from public and private schools. It tracks them at ages 9, 13 and 17, regardless of grade level, and compares their performance using tests that take about an hour and features mostly multiple-choice questions.
Here are five things to know about academic progress since the 1970s, according to the 2012 report.
9-year-olds and 13-year-olds outscore 1970s counterparts
Indeed, those kids scored higher in reading and math. In reading, 9-year-olds and 13-year-olds improved at every level, so even the lowest-performing kids now are ahead of the lowest-performing kids then. In fact, kids in the low and middle range showed the greatest gains.
17-year-olds? Not so much
Seventeen-year-old students aren't scoring better in reading and math, but their scores aren't falling, either. In reading, the lowest-performing 17-year-olds made gains since the 1970s, as did lower- and middle-performing 17-year-olds in math. But scores overall are about the same as in the early 1970s -- and that might not be all bad. In a conference call with reporters, Peggy Carr, associate commissioner of the National Center for Education Statistics' assessment division, pointed out that there are far fewer dropouts than in the 1970s, but even with more kids in school, performance has remained steady.
Gender gaps are shrinking
Just as in the 1970s, girls perform better in reading, and boys perform better in math.
But female students are narrowing the math gap, or even eliminating it. "In 2012, there were no significant gender gaps in mathematics at age 9 and 13," the report says. "At age 17, male students scored higher in mathematics than female students. The gender gap in 2012 at age 17, however, was narrower than in 1973 due to the increase in the average score for female students."
Meanwhile, male students are squeezing the gap in reading by showing significant improvement at age 9.
Black and Hispanic students are making gains
Consider just how much students' demographics have changed: In 1978, 80% of U.S. students were White, 13% were Black, 6% were Hispanic and 1% were Asian. In 2012, 56% of students were White, 15% were Black, 21% were Hispanic and 6% were Asian.
White students still perform better than Black and Hispanic students in reading, but the gaps between White and Black and White and Hispanic are narrower for all ages. It's particularly noticeable among 9-year-olds: "The average score for Black students was 36 points higher in 2012 than in 1971 ... and the score for White students was 15 points higher," the report says. "The average score for Hispanic students increased 25 points from 1975, and the score for White students increased 12 points."
In math, White students performed better overall, but Black and Hispanic students made larger gains than White students since 1973.
Take another look at that summer reading list
At age 9, 53% of students say they read for fun at home almost every day. By age 13, it's 27%. At 17, it's down to 19%. The percentages for 9-year-olds have remained the same since 1984, when the question was first asked, but it has decreased over time for 13- and 17-year-olds. Why does it matter?
"At all three ages, students who reported reading for fun almost daily or once or twice a week scored higher than did students who reported reading for fun a few times a year or less," the report says.