For something that was meant to simplify education standards in America, many find Common Core to be quite confusing. Here, we break down not just what it is, but how it’s implemented and measured, along with some of the pros and cons.
In a Nutshell
Common Core is the set of academic standards in mathematics and English language arts that define what a student should learn by the end of each school year in Kindergarten through 12th grade.
Common Core Standards were set in 2009 by the Council of Chief State School Officers (CCSSO) and the National Governors Association Center for Best Practices (NGA Center). These two entities joined forces in a state-led effort to develop Common Core. They worked with teachers, administrators, university professors, representatives from testing companies, and other education experts to create a framework that educators across the country could use.
Who’s in and who’s out?
Even though Common Core was meant to create a singular academic standard across the nation, just 34 states and the District of Columbia always have been, and still are, fully committed to Common Core, have implemented it, and are participating in standardized testing. (In the map below, those states are in dark blue.) Other states only adopted a portion of the standards, or repealed certain parts of the standards after adopting them, or created their own version of Common Core without ever adopting the national standards in the first place. In many cases, a state’s own version of Common Core is aligned closely enough with the national version to “count,” but is still technically a state-specific plan. Other states have implemented the standards but have opted out, or are in the process of opting out, of testing. (Both Wikipedia and Common Core’s website provide state-by-state details.) Additionally, the U.S. Virgin Islands, Guam, the Northern Mariana Islands, and the American Samoa Islands have adopted the standards, though Puerto Rico has not.
It wasn’t always this way, though. When Common Core was first introduced, all states but Alaska, Nebraska, Texas, and Virginia voluntarily adopted it, with a handful of additional states adopting it partially. However, many states have repealed parts of the standards or repealed them entirely. (See map for details.)

Dark blue: states that have adopted the Standards. Light blue: states that have partially adopted or partially repealed the Standards. Yellow: States that adopted but later repealed the Standards. Brown: states that never adopted the Standards.
(Public domain.) [CC BY-SA 4.0], via Wikimedia Commons
Are private schools exempt?
Technically, private schools are not required to implement Common Core standards even in states where the program has been implemented. However, many private schools have signed on anyway for two main reasons:
- Private schools may lose access to federal funds if they reject Common Core.
- The SAT and ACT tests are influenced by Common Core, so many private schools find themselves teaching to the standards regardless.
What are the standards?
Specific academic standards for Common Core are laid out for every grade, from Kindergarten to 12th grade. Highly detailed explanations of both mathematics and English Language Arts are available on Common Core’s main website, but to give a sense of what’s contained within, here’s a very basic breakdown:
English Language Arts
Under the ELA umbrella, dozens of goals are defined within several different categories:
- Literature
- Informational Text
- Foundational Skills (phonics, word recognition, fluency, etc.)
- Writing
- Speaking and Listening Standards
- Language Standards (vocabulary, etc.)
Those same broad categories span all K through 12 grades, with the exception of Foundational Skills, which drops in 6th grade. By the end of each grade, a student should have a deeper knowledge and stronger mastery of each of these skill sets.
From there, the standards become quite granular. Literature alone, for example, includes 10 specific sub-goals that increase in difficulty at each level. One literature standard for Kindergarteners is to “ask and answer questions about key details in a text.” By the end of 5th grade, students are expected to “quote accurately from a text when explaining what the text says explicitly and when drawing inferences from the text.”
Mathematics
The Common Core standards for math are broken down differently. In Kindergarten through 5th grade, most of the overarching categories — Operations & Algebraic Thinking, Number & Operations in Base 10, Measurement & Data, and Geometry — remain the same, with the standards for learning increasing in difficulty each year. But there’s some variation. For example, Kindergarteners study Counting & Cardinality while 3rd grade incorporates a new category, Fractions. From there through 12th grade, new concepts are introduced and mastered, such as Statistics & Probability and Trigonomic Functions.
How is the success of Common Core measured?
States have the flexibility to determine how they measure Common Core, at least technically. In practice, many participating states are working within two consortia — Partnership for Assessment of Readiness for College and Careers (PARCC) and the Smarter Balanced Assessment Consortium (Smarter Balanced) — to develop standardized testing. The first Common Core-based standardized tests developed by these groups were administered in the 2014-2015 school year, and test development is still considered a work in progress. States continue to be free, however, to develop their own testing system.
The underlying reason for supporting it is as obvious as it is vital: The main benefit of Common Core is its ability to standardize.
What supporters of Common Core say
Those who are in favor of Common Core cite lots of different reasons including increased rigor in classrooms where it was lacking, and enhanced tools for monitoring student success.
But the underlying reason for supporting it is as obvious as it is vital: The main benefit of Common Core is its ability to standardize. Prior to Common Core, academic standards varied greatly from state to state, but Common Core has led to a more stable benchmark against which to measure all students.
Before Common Core, there also wasn’t a system in place to easily compare performance from state to state. This across-the-board approach is making that task easier. Common Core is also said to more directly measure up to international standards, which may put the United States on course to be more competitive with other countries when it comes to education.
What critics of Common Core say
Many complain that the standards force teachers to “teach to the test,” which can be an issue both for teachers and for students.
Common Core also has its share of detractors.
Many complain that the standards force teachers to “teach to the test,” which can be an issue both for teachers and for students. Students who are high achievers in the classroom may not test well, and lower standardized test scores can affect their placement in classes, which may jeopardize their academic future.
In turn, teachers whose students perform well in the classroom but test poorly may see a negative impact on their salary, or it could affect their seniority or placement, and could eventually even lead to termination. Some argue this is an unfair way to evaluate teachers.
Some have even criticized the tests themselves. In 2016, for example, teachers in New York reported misprints in the test booklets and poorly constructed questions. They also said some of the questions were too advanced for the children.
The bottom line
Common Core is still in its infancy, and its impact may not be known until the dust settles and the kinks are ironed out, or until it’s repealed in enough states to be considered defunct. Still, the best way to see how Common Core fits into your or your child’s education is to look up the standards in your state to gain an understanding of what’s being implemented in your local classrooms.
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