UPDATED

If you’ve been wondering how many states had significant issues with test participation last spring, there’s an answer from the U.S. Department of Education.

Twelve states have received letters from the Education Department in recent months asking them to address lower-than-required participation rates on state exams for groups of students or districts, or statewide.

The states to receive these letters are: California, Colorado, Connecticut, Delaware, Idaho, Maine, New York, North Carolina, Oregon, Rhode Island, Washington, and Wisconsin. (Click the individual link to see each state’s letter from the department.) Some of the copies of the letters are undated, but several were sent in either early November or early December. UPDATE: Illinois also received a letter from the department dated Dec. 23 stating that at least one district had not met the participation rate requirement.

The Education Department’s letters ask states to specify how they will address their local or state participation rates for the 2015-16 school year. The department includes possible examples of how states could act, such as lowering a school or district’s rating on state accountability systems, and counting non-participating students as not proficient for accountability purposes.

On Tuesday, the department also released guidance for states in which it said that under the Every Student Succeeds Act, states need plans to address situations in which participation rates that dip below the required 95 percent.

The testing opt-out movement became a prominent story in education this year, particularly in some of the states listed above, like New York. Reasons for skepticism and opposition to the test included backlash to the Common Core State Standards, concerns about the amount of testing, and teacher evaluations that factored in test scores.

So what were some of the various statewide and other test-participation issues encountered by each state?

• California reported that it did not assess at least 95 percent of its students, or individual student subgroups, on both the English/language arts and math exams. UPDATE: The California Department of Education has told me that in fact, with respect to statewide participation on exams, California did in fact clear the 95 percent threshold; the state reported that 97 percent of students took the Smarter Balanced exams. Some districts in California did not meet the 95 percent threshold, an issue the Education Department letter also specifies might have been the issue with respect to participation on the state exams.
• Colorado missed the 95-percent requirement for all students, and participation rates in grades 7 through high school were particularly low, ranging from 50 percent to 89 percent in E/LA and 60 percent to 89 percent in math.
• Connecticut did not assess at least 95 percent of all its students.
• Delaware did not assess at least 95 percent of its English-language learners and high school students.
• Idaho had “at least” one district that did not assess 95 percent of its students on both exams. (The exact number of these districts isn’t specified.)
• Maine did not assess at least 95 percent of all its students on both exams.
• New York did not assess at least 95 percent of all students, and several districts “throughout the State had significant issues with respect to participation rates.” (The exact number of these districts isn’t specified.)
• North Carolina missed participation rate targets for English-language learners and students with disabilities.
• Oregon did not assess at least 95 percent of all students, and 21 districts did not assess at least 95 percent of all their students.
• Rhode Island did not assess at least 95 percent of all students, and “at least” 34 districts did not assess 95 percent of all their students.
• Washington state did not assess at least 95 percent of all students.
• Wisconsin had “some” districts that did not assess at least 95 percent of all students. (The exact number of these districts isn’t specified.)

In each letter, the department stresses the importance of a “high-quality, annual Statewide assessment system” to provide better information to local leaders and educators.

The department also specified that if a state fails to address the issue, the department might withhold a portion of the state’s Title I funds, and that other state funds from Title II, Title III, and Title VI, among others, could be put at risk.