While the K-8 common-core mathematics standards have garnered praise from many mathematicians and math educators, even some of the most ardent supporters of the Common Core State Standards agree that the high school math standards have weaknesses and should be revisited.

There’s less agreement, though, on exactly where the high school standards fall short: Some say they’re too dense, while others argue they don’t adequately prepare students for college. Still others point to specific skills the standards fail to address. One expert even claims that a standard is completely missing from the published document—one that was there in the drafts.

The high school standards were tougher to reach a consensus on, experts involved in writing them said. “Everybody had their pet topic. But all those topics, they’re all good things for kids to learn,” said William G. McCallum, a math professor at the University of Arizona in Tucson and one of the lead writers of the common standards. “High school was just hard. The whole exercise was trying to bring people together to agree on things.”

As some experts see it, the high school standards were shortchanged because reviewers were rushed looking over them. “The amount of time given to the high school standards was definitely inadequate,” said Hung-Hsi Wu, a professor emeritus of mathematics at the University of California, Berkeley, who served on the standards’ development team. “We were so busy with K-8.”

The criticisms come as the first round of tests aligned to the math standards roll out this spring in most states.

Forty-two states and the District of Columbia have adopted the common-core math standards, and many have been implementing them in classrooms for several years now.

### Evaluating Depth

One of the ways the common core aims to change mathematics instruction is by emphasizing “focus,” or by teaching fewer topics more deeply. The standards, as the common-core document states, “ask math teachers to significantly narrow and deepen the way time and energy are spent in the classroom.”

But some educators say there isn’t less content at the high school level—indeed, there may be more than there was previously.

The standards are “very dense,” said Bill Barnes, a secondary math coordinator for the 52,000-student Howard County public school system in Maryland. “I don’t know that the authors of the common core were able to achieve the kind of focus [in high school] they were able to achieve in the early grades.”

While students in Mr. Barnes’ district are technically being introduced to fewer individual standards now—in Algebra I, for instance, they went from around 70 standards to 30—each of the new standards contains about “three or four objectives from the old curriculum,” he said. “I don’t think we’re realizing a reduction in standards.” Districts can choose which standards are taught in which high school courses, though the number of standards students are responsible for by the end of high school remains the same.

“Each standard has so many ideas built into it, you really have to sit down and think through all the implications of that,” said Bobson Wong, a math teacher at Bayside High School in Bayside, N.Y. “I could easily make each of these courses a two-year course.”

Mr. Wong, who has twice received master teacher fellowships from the New York City-based teacher-training group Math for America, said the standards are “vague, embedding many difficult concepts in one sentence.” For example, he pointed to the following geometry standard:

“Prove theorems about triangles. Theorems include: measures of interior angles of a triangle sum to 180°; base angles of isosceles triangles are congruent; the segment joining midpoints of two sides of a triangle is parallel to the third side and half the length; the medians of a triangle meet at a point.”

“In one sentence, this standard summarizes almost half a year’s worth of proofs,” said Mr. Wong.

### Thin on Content?

On the other hand, though, several mathematicians have argued the high school standards don’t contain enough content, in terms of both breadth and depth.

Unlike the K-8 standards, the high school standards are grouped by topic, and not by grade level or course. Mr. Wu, an adamant supporter of the standards, highlighted “some obvious curricular gaps” he saw in the standards in 2011 when he wrote out two proposals for how the standards could be grouped into courses. Among the gaps listed were: “the explicit definition of congruence and similarity transformation, the explicit definition of an inverse function, an explicit explanation of why the graph of a linear equation of two variables is a line, etc.”

One of the most vocal opponents of the math standards, R. James Milgram, a professor emeritus in mathematics at Stanford University, has long contended that the high school standards don’t contain enough content to prepare students for college.

“They’re very low level,” said Mr. Milgram, who served on the standards’ validation committee but refused to sign off on their approval. He points to a study for the U.S. Department of Education, called “The Toolbox Revisited: Paths to Degree Completion From High School Through College,” indicating that, of the students from the high school class of 1992 whose highest level of math was Algebra II, just 39 percent obtained bachelor’s degrees.

Meanwhile, about 75 percent of students who went through precalculus eventually graduated with a bachelor’s. Mr. Milgram fears that students will not take courses beyond Algebra II, which the data show are correlated with an increased likelihood of college graduation, because the common core does not explicitly require them. “In low socioeconomic areas, [those courses] simply won’t be offered,” he said. “They’re not offered now, and there’s no reason to assume that’s going to change.”

The common core does include additional standards, known as “plus standards,” which go beyond Algebra II but will not be tested. And while the standards generally assume students will not take Algebra I until 9th grade, the appendix shows an accelerated pathway, in which students combine three courses into two years. Districts also have leeway in how they organize courses.

Several experts have said the standards suffered because the review process was rushed. “We didn’t have enough time to really polish the high school standards,” said Mr. Wu.

Mr. McCallum explained that the drafts went out to reviewers in succession—first K-5, then K-8, and finally K-8 plus high school. “So high school didn’t get as many read-throughs as other standards,” he said. “You could always use more time. But it’s not like it would’ve been a good idea to do it the other way around. There’s no point in getting high school right if you get K-8 wrong.”

“I think people were enough concerned about elementary and middle school that they focused more on that in the review,” said Richard A. Askey, a professor emeritus at the University of Wisconsin-Madison, who was a member of the math standards’ feedback group.

### Concerns About Haste

In fact, he said, the process toward the end was so hurried that an entire high school standard was left out of the final draft. Mr. Askey noticed the omission of a geometry standard—one that explains that, under similarity transformations, area scales by squares and volume by cubes—after the document was published. “It’s mentioned in Appendix A but isn’t in the standards,” he said. “And it was there in one of the drafts.”

Mr. McCallum chose not to offer a response. He did, however, point out that states can add standards, and that California added a standard to address the geometry skill Mr. Askey said was missing.

According to Chris Minnich, the executive director of the Council of Chief State School Officers, the Washington-based group that led the standards development, “the entire process took about 14 months.” However, as the common-core website notes, independent reviews of the K-12 grade by grade college- and career-readiness standards—the document that would eventually become the common core—did not begin until January 2010.

The common standards were officially released five months later, after being pushed back several times so the writers could incorporate more feedback.

There’s no formal mechanism in place for a wholesale review of the common core, but it’s likely that states will—as they always have—review their standards at times and decide whether they need to be altered.

Francis M. “Skip” Fennell, a professor of education at McDaniel College in Westminster, Md., and a former president of the National Council of Teachers of Mathematics, says the standards should be reviewed once there are data on how much students have learned under them. “In my mind, standards should be a work in progress,” said Mr. Fennell, who also worked on the standards development team. “I think you could say that about any set of standards in any subject. Wouldn’t you want to revisit them periodically?”

Until then, even some of those with criticisms say they’re pleased the common core is in high school classrooms.

“These [standards] are the best that have been done in the U.S.,” said Mr. Askey. “I want them to succeed.”