By Miriam Gamoran Sherin, Special to CNN

Editor’s note: Miriam Gamoran Sherin, a public voices fellow with the OpEd Project, is professor of education and social policy at Northwestern University and mother of three.

(CNN) – In the past several weeks, middle and high school students across the country brought home their first-quarter report cards. Many make a push to improve scores and grades before the holidays, and over winter break, some will study for final exams, knowing those results are a major component of their semester class ranks.

For many families, report cards serve as the key measure of a child’s success in school.  They’re assigned so much importance, grades can be the source of conflict and tension at a time when parents and their children could be celebrating the winter holidays peacefully.

But what if the report card itself is not so valuable? What do grades actually tell us about our children’s learning?

Not as much as we think.

Grades are one measure of our children’s success, but perhaps not the most important one. The level of learning is what matters.

My 12-year-old daughter is getting a B in her seventh-grade math class, and learning much more than last year, when she was getting an A. Her sixth-grade math class focused on rote computation with study guides that were almost identical to the following day’s test. This year, her class focuses on mathematical problem-solving. The tests challenge students to apply what they know.

The letter grade printed on a report card is usually a fairly straightforward combination of effort and execution: 10% homework, 30% quizzes, 60% tests. Assessing a student’s learning is not as easily measured.

It involves looking across a variety of assessment types, talking with students’ about their thinking, listening to their questions and seeing how students respond to opportunities for revision. Your child’s grade may or may not reflect this variety of assessments.

Research also raises questions about the role of grades in representing students’ learning. A 2012 study at the University of Windsor  corroborates more than a decade of research that grading practices can undermine student’s motivation to learn. In addition, a 2012 study led by the University of Pennsylvania finds that report card grades more often reflect students’ self-control than what students know and understand. And a 2012 report on the Ethics of Grading highlights that grades are too often a subjective measure of achievement.

In light of such findings, school districts in Kentucky, Florida and California have eliminated traditional report card grades in favor of assessments that gauge students’ mastery in specific areas and separates success on homework completion from students’ achievement.

Similarly, a handful of colleges across the United States, such as Bard College, Brown University and Hampshire College, offer students the option of receiving narrative descriptions of their performance instead of or in addition to traditional letter grades.

What does this mean for parents?

As you review your child’s report card, instead of focusing on the grade alone, try to find out what your child learned in class this quarter. Take a look at the work your child produced and have your child tell you about a few pieces. Discuss whether the class was too easy, too hard or just right. Ask your child if his grade reflects how much was learned – you’d be surprised at how articulate teens can be about what it takes to get an A in certain classes. See which subject she thinks she learned the most in and why. Is there a class where he or she could have learned more?

Of course, grades do matter in the wider world. Hundreds of thousands of high school seniors will submit college applications from now until January for the following school year. Yes, transcripts, grade point averages and class ranking are key factors in admission decisions.

Some even argue that grades predict future earnings.

So it is impossible to ignore them. Still, I’d rather focus on my children learning important concepts and strategies for thinking, as well as tools for learning how to write, communicate and solve complex problems. That all must matter more for the kind of people they become and the ideas and work they pursue than a single letter.

Until keener, alternative assessments are adopted at the elementary and high school levels in this country, we will have to take our A, B, Cs for what they are worth. And for many students and their parents, they are not worth much.

Spending the holidays away from bickering about grades and report cards might make these weeks happier for everyone involved. Instead, parents and children can add effective learning to their wish lists for a happier New Year.

The opinions expressed in this commentary are solely those of Miriam Gamoran Sherin.