With its intricate mysteries of quadratics, logarithms and imaginary numbers, Algebra II often provokes a lament from high-schoolers.

What exactly does this have to do with real life?

The answer: maybe more than anyone could have guessed.

Of all of the classes offered in high school, Algebra II is the leading predictor of college and work success, according to research that has launched a growing national movement to require it of graduates.

In recent years, 20 states and the District have moved to raise graduation requirements to include Algebra II, and its complexities are being demanded of more and more students.

The effort has been led by Achieve, a group organized by governors and business leaders and funded by corporations and their foundations, to improve the skills of the workforce. Although U.S. economic strength has been attributed in part to high levels of education, the workforce is lagging in the percentage of younger workers with college degrees, according to the Organization of Economic Cooperation and Development.

But exactly how to raise the education levels of the U.S. workforce is a matter of debate. And whether learning Algebra II causes students to fare better in life, or whether it is merely correlated with them doing better — because smart, motivated kids take Algebra II — isn’t clear. Meanwhile, some worry that Algebra II requirements are leading some young people to quit school.

The District this year joins other states requiring high school graduates to meet the Achieve standards that include Algebra II; Maryland and Virginia do not.

But no state has pushed Algebra II more than Arkansas, which began requiring the class last year for most graduates and assesses how well students have done with a rigorous test — one of only two states to administer the test. Only 13 percent of those who took the Algebra II test in Arkansas were deemed “prepared” or better, but state officials said they are aiming to raise that figure rather than lower standards.

“All those numbers and letters, it’s like another language, like hieroglyphics,” said Tiffany Woodle, a Conway High School student and an aspiring beauty salon owner. “It obviously says something. I’m just not sure what, sometimes.”

Achieve and other educational groups, which spent years defining standards to better prepare students for college and work, quickly fastened on Algebra II as a fundamental component.

One of the key studies supporting the Algebra II focus was conducted by Anthony Carnevale and Alice Desrochers, then both at the Educational Testing Service. They used a data set that followed a group of students from 1988 to 2000, from eighth grade to a time when most were working.

The study showed that of those who held top-tier jobs, 84 percent had taken Algebra II or a higher class as their last high school math course. Only 50 percent of employees in the bottom tier had taken Algebra II.

“Algebra II does increase the likelihood of being employed in a good job,” they reported, although warning that many factors come into play.

To check the Algebra II findings against the “real world,” the Achieve researchers then asked college professors and employers to identify which skills are necessary to succeed.

Somewhat to their surprise, they found that whether students were going into work or college, they needed the skills taught in Algebra II. Other independent studies backed them up. One conducted by U.S. Department of Education researcher Clifford Adelman found that students who took Algebra II and at least one more math course attained “momentum” toward receiving a bachelor’s degree.

“There was a fair amount of judgment that went into this,” said Michael Cohen, president of Achieve and a former assistant secretary of education in the Clinton administration. But “it turns out to get the skills needed, students had to reach Algebra II.”

The push for Algebra II had begun, and it was embraced by many states.

But not everyone is convinced that Algebra II is the answer.

Among the skeptics is Carnevale, one of the researchers who reported the link between Algebra II and good jobs. He warns against thinking of Algebra II as a cause of students getting good jobs merely because it is correlated with success.

“The causal relationship is very, very weak,” he said. “Most people don’t use Algebra II in college, let alone in real life. The state governments need to be careful with this.”

The danger, he said, is leaving some kids behind by “getting locked into a one-size-fits-all curriculum.”

Conway, about 30 miles north of Little Rock, is a small town with rural roots; the annual summer festival is known as Toad Suck Daze, a local reference to a time when steamboats worked the Arkansas River. The Conway High School mascot is the mythical Wampus Cat. About 44 percent of its students have qualified for free or reduced-price lunches.

Yet its students have performed better on the test than all but a handful of other districts.

Among the 15 students gathered recently in an Algebra II class, however, the difficulties were apparent. Eight of the students said it was the hardest class they had ever taken, and several questioned why they needed it.

Garrett Baldwin, an outfielder on the baseball team who wants to be a firefighter, said, “I’d enjoy it — if I ever knew what was going on.”

And Hunter Venable, who likes nothing better than duck hunting — “it’s all I do” — snorted at a question about the real-life relevance of Algebra II.

“Ass-um-topes,” he said, intentionally stumbling over the word “asymptotes,” which they have been studying. “I have no idea what those are.”

In Arkansas and elsewhere, educators worry that the class requirement could lead students to quit.

“Some students, who’ve gotten behind over the years, are never going to pass Algebra II,” said Teresa George, a veteran teacher, after a morning coaxing students through rational functions. If it becomes an obstacle to graduation, “then you’ve lost them. And what’s their next option?”

For proof of the usefulness of Algebra II, students need look no farther than the largest employers in Conway.

Acxiom, a database company that employs 2,100 in the town, hires software and database developers, most of whom have bachelor’s degrees in technical fields. For them, Algebra II skills are a prerequisite. Similarly, at Snap-on Equipment, a plant that employs 170 making the sophisticated gears that garages use to align and balance tires, most production jobs require associate’s degrees in electronics.

By contrast, at the Kimberly-Clark plant, which makes feminine hygiene and adult incontinence products, production workers need only a high school education. The jobs pay 11 to $20 an hour, and when 70 spots recently came open during an expansion, about 2,000 people applied.

“We’re looking for people with the ability to think critically,” said Jeremy Cannady, until recently a manufacturing efficiency coordinator at the plant. But “not the ability to do exponential functions or logarithms.”

Whatever the demands for Algebra II, state officials are loath to lower the bar. The state has ranked near the bottom in the percentage of adults with bachelor’s degrees, just above West Virginia. So despite the complaints, students should be made to try, they say.

“Everybody else in the world believes it takes effort when it comes to math,” said Gayle Potter, associate director of academic standards in the Arkansas education department. “In America, we seem to believe that there is a math gene, and if it’s not there, forget it. But math is challenging, and you have to work at it.”