State testing is among the most widely used tools for evaluating public schools, with exams given annually to students of all grade levels. Though standardized tests have a history of mishaps — most recently in Tennessee, where officials suspended elementary and middle school testing because of a failure by vendors to deliver tests on time — they remain a valued method of assessing performance.

With this in mind, StartClass ranked the states based on their performance on assessment test scores using data from the National Assessment of Educational Progress, also known as the "Nation's Report Card." The NAEP is America's "largest continuing and nationally representative assessment of what our nation’s students know and can do in select subjects" and was first administered in 1969. These results are for states from the 2015 reading and math assessments for Grades 4 and 8, both deemed critical junctures in academic achievement. Results for Grade 12 from 2015 from each state have not yet been released.

States are ranked based on the average percent of students who scored proficient or above on math and reading tests for the two grades. The math assessment measures students' knowledge and skill in mathematics and their ability to apply their knowledge in problem-solving situations. The reading assessment measures students' reading comprehension by asking them to read grade-appropriate materials and answer questions based on what they have read.

Note: In the event of ties, the state with the higher Grade 8 math proficiency rate was ranked higher on the list.

Average percent of students at or above proficient: 22.8 percent

Percent of students at or above proficient in:

• Grade 4 Math: 27 percent
• Grade 4 Reading: 23 percent
• Grade 8 Math: 21 percent
• Grade 8 Reading: 20 percent

Average percent of students at or above proficient: 24.5 percent

Percent of students at or above proficient in:

• Grade 4 Math: 26 percent
• Grade 4 Reading: 29 percent
• Grade 8 Math: 17 percent
• Grade 8 Reading: 26 percent

Average percent of students at or above proficient: 24.5 percent

Percent of students at or above proficient in:

• Grade 4 Math: 30 percent
• Grade 4 Reading: 26 percent
• Grade 8 Math: 22 percent
• Grade 8 Reading: 20 percent

Average percent of students at or above proficient: 25 percent

Percent of students at or above proficient in:

• Grade 4 Math: 30 percent
• Grade 4 Reading: 29 percent
• Grade 8 Math: 18 percent
• Grade 8 Reading: 23 percent

Average percent of students at or above proficient: 27.8 percent

Percent of students at or above proficient in:

• Grade 4 Math: 33 percent
• Grade 4 Reading: 30 percent
• Grade 8 Math: 21 percent
• Grade 8 Reading: 27 percent

Average percent of students at or above proficient: 28 percent

Percent of students at or above proficient in:

• Grade 4 Math: 29 percent
• Grade 4 Reading: 28 percent
• Grade 8 Math: 27 percent
• Grade 8 Reading: 28 percent

Average percent of students at or above proficient: 28.5 percent

Percent of students at or above proficient in:

• Grade 4 Math: 32 percent
• Grade 4 Reading: 29 percent
• Grade 8 Math: 26 percent
• Grade 8 Reading: 27 percent

Average percent of students at or above proficient: 29 percent

Percent of students at or above proficient in:

• Grade 4 Math: 32 percent
• Grade 4 Reading: 32 percent
• Grade 8 Math: 25 percent
• Grade 8 Reading: 27 percent

Average percent of students at or above proficient: 30.5 percent

Percent of students at or above proficient in:

• Grade 4 Math: 37 percent
• Grade 4 Reading: 33 percent
• Grade 8 Math: 23 percent
• Grade 8 Reading: 29 percent

Average percent of students at or above proficient: 30.8 percent

Percent of students at or above proficient in:

• Grade 4 Math: 36 percent
• Grade 4 Reading: 33 percent
• Grade 8 Math: 26 percent
• Grade 8 Reading: 28 percent

Average percent of students at or above proficient: 30.8 percent

Percent of students at or above proficient in:

• Grade 4 Math: 38 percent
• Grade 4 Reading: 29 percent
• Grade 8 Math: 30 percent
• Grade 8 Reading: 26 percent

Average percent of students at or above proficient: 31 percent

Percent of students at or above proficient in:

• Grade 4 Math: 34 percent
• Grade 4 Reading: 29 percent
• Grade 8 Math: 29 percent
• Grade 8 Reading: 32 percent

Average percent of students at or above proficient: 31.8 percent

Percent of students at or above proficient in:

• Grade 4 Math: 35 percent
• Grade 4 Reading: 34 percent
• Grade 8 Math: 28 percent
• Grade 8 Reading: 30 percent

Average percent of students at or above proficient: 32 percent

Percent of students at or above proficient in:

• Grade 4 Math: 35 percent
• Grade 4 Reading: 30 percent
• Grade 8 Math: 32 percent
• Grade 8 Reading: 31 percent

Average percent of students at or above proficient: 33.5 percent

Percent of students at or above proficient in:

• Grade 4 Math: 38 percent
• Grade 4 Reading: 30 percent
• Grade 8 Math: 35 percent
• Grade 8 Reading: 31 percent

Average percent of students at or above proficient: 33.8 percent

Percent of students at or above proficient in:

• Grade 4 Math: 40 percent
• Grade 4 Reading: 33 percent
• Grade 8 Math: 29 percent
• Grade 8 Reading: 33 percent

Average percent of students at or above proficient: 33.8 percent

Percent of students at or above proficient in:

• Grade 4 Math: 37 percent
• Grade 4 Reading: 37 percent
• Grade 8 Math: 30 percent
• Grade 8 Reading: 31 percent

Average percent of students at or above proficient: 33.8 percent

Percent of students at or above proficient in:

• Grade 4 Math: 35 percent
• Grade 4 Reading: 36 percent
• Grade 8 Math: 31 percent
• Grade 8 Reading: 33 percent

Average percent of students at or above proficient: 33.8 percent

Percent of students at or above proficient in:

• Grade 4 Math: 44 percent
• Grade 4 Reading: 31 percent
• Grade 8 Math: 32 percent
• Grade 8 Reading: 28 percent

Average percent of students at or above proficient: 34.3 percent

Percent of students at or above proficient in:

• Grade 4 Math: 42 percent
• Grade 4 Reading: 39 percent
• Grade 8 Math: 26 percent
• Grade 8 Reading: 30 percent

Average percent of students at or above proficient: 34.8 percent

Percent of students at or above proficient in:

• Grade 4 Math: 37 percent
• Grade 4 Reading: 35 percent
• Grade 8 Math: 32 percent
• Grade 8 Reading: 35 percent

Average percent of students at or above proficient: 35.3 percent

Percent of students at or above proficient in:

• Grade 4 Math: 38 percent
• Grade 4 Reading: 36 percent
• Grade 8 Math: 31 percent
• Grade 8 Reading: 36 percent

Average percent of students at or above proficient: 35.3 percent

Percent of students at or above proficient in:

• Grade 4 Math: 37 percent
• Grade 4 Reading: 34 percent
• Grade 8 Math: 34 percent
• Grade 8 Reading: 36 percent

Average percent of students at or above proficient: 35.8 percent

Percent of students at or above proficient in:

• Grade 4 Math: 40 percent
• Grade 4 Reading: 35 percent
• Grade 8 Math: 34 percent
• Grade 8 Reading: 34 percent

Average percent of students at or above proficient: 36 percent

Percent of students at or above proficient in:

• Grade 4 Math: 40 percent
• Grade 4 Reading: 40 percent
• Grade 8 Math: 28 percent
• Grade 8 Reading: 36 percent

Average percent of students at or above proficient: 36 percent

Percent of students at or above proficient in:

• Grade 4 Math: 37 percent
• Grade 4 Reading: 40 percent
• Grade 8 Math: 32 percent
• Grade 8 Reading: 35 percent

Average percent of students at or above proficient: 36 percent

Percent of students at or above proficient in:

• Grade 4 Math: 41 percent
• Grade 4 Reading: 35 percent
• Grade 8 Math: 33 percent
• Grade 8 Reading: 35 percent

Average percent of students at or above proficient: 36.3 percent

Percent of students at or above proficient in:

• Grade 4 Math: 44 percent
• Grade 4 Reading: 38 percent
• Grade 8 Math: 33 percent
• Grade 8 Reading: 30 percent

Average percent of students at or above proficient: 36.3 percent

Percent of students at or above proficient in:

• Grade 4 Math: 38 percent
• Grade 4 Reading: 36 percent
• Grade 8 Math: 34 percent
• Grade 8 Reading: 37 percent

Average percent of students at or above proficient: 37 percent

Percent of students at or above proficient in:

• Grade 4 Math: 41 percent
• Grade 4 Reading: 36 percent
• Grade 8 Math: 35 percent
• Grade 8 Reading: 36 percent

Average percent of students at or above proficient: 37.3 percent

Percent of students at or above proficient in:

• Grade 4 Math: 40 percent
• Grade 4 Reading: 37 percent
• Grade 8 Math: 35 percent
• Grade 8 Reading: 37 percent

Average percent of students at or above proficient: 38.5 percent

Percent of students at or above proficient in:

• Grade 4 Math: 45 percent
• Grade 4 Reading: 38 percent
• Grade 8 Math: 35 percent
• Grade 8 Reading: 36 percent

Average percent of students at or above proficient: 38.5 percent

Percent of students at or above proficient in:

• Grade 4 Math: 41 percent
• Grade 4 Reading: 37 percent
• Grade 8 Math: 39 percent
• Grade 8 Reading: 37 percent

Average percent of students at or above proficient: 38.8 percent

Percent of students at or above proficient in:

• Grade 4 Math: 44 percent
• Grade 4 Reading: 38 percent
• Grade 8 Math: 37 percent
• Grade 8 Reading: 36 percent

Average percent of students at or above proficient: 38.8 percent

Percent of students at or above proficient in:

• Grade 4 Math: 45 percent
• Grade 4 Reading: 37 percent
• Grade 8 Math: 39 percent
• Grade 8 Reading: 34 percent

Average percent of students at or above proficient: 39.3 percent

Percent of students at or above proficient in:

• Grade 4 Math: 43 percent
• Grade 4 Reading: 39 percent
• Grade 8 Math: 37 percent
• Grade 8 Reading: 38 percent

Average percent of students at or above proficient: 40 percent

Percent of students at or above proficient in:

• Grade 4 Math: 48 percent
• Grade 4 Reading: 41 percent
• Grade 8 Math: 35 percent
• Grade 8 Reading: 36 percent

Average percent of students at or above proficient: 40 percent

Percent of students at or above proficient in:

• Grade 4 Math: 44 percent
• Grade 4 Reading: 40 percent
• Grade 8 Math: 38 percent
• Grade 8 Reading: 38 percent

Average percent of students at or above proficient: 40.3 percent

Percent of students at or above proficient in:

• Grade 4 Math: 45 percent
• Grade 4 Reading: 41 percent
• Grade 8 Math: 36 percent
• Grade 8 Reading: 39 percent

Average percent of students at or above proficient: 40.5 percent

Percent of students at or above proficient in:

• Grade 4 Math: 46 percent
• Grade 4 Reading: 40 percent
• Grade 8 Math: 38 percent
• Grade 8 Reading: 38 percent

Average percent of students at or above proficient: 40.5 percent

Percent of students at or above proficient in:

• Grade 4 Math: 45 percent
• Grade 4 Reading: 37 percent
• Grade 8 Math: 41 percent
• Grade 8 Reading: 39 percent

Average percent of students at or above proficient: 40.8 percent

Percent of students at or above proficient in:

• Grade 4 Math: 41 percent
• Grade 4 Reading: 43 percent
• Grade 8 Math: 36 percent
• Grade 8 Reading: 43 percent

Average percent of students at or above proficient: 40.8 percent

Percent of students at or above proficient in:

• Grade 4 Math: 47 percent
• Grade 4 Reading: 40 percent
• Grade 8 Math: 39 percent
• Grade 8 Reading: 37 percent

Average percent of students at or above proficient: 41 percent

Percent of students at or above proficient in:

• Grade 4 Math: 47 percent
• Grade 4 Reading: 43 percent
• Grade 8 Math: 38 percent
• Grade 8 Reading: 36 percent

Average percent of students at or above proficient: 41.5 percent

Percent of students at or above proficient in:

• Grade 4 Math: 50 percent
• Grade 4 Reading: 40 percent
• Grade 8 Math: 39 percent
• Grade 8 Reading: 37 percent

Average percent of students at or above proficient: 43.5 percent

Percent of students at or above proficient in:

• Grade 4 Math: 43 percent
• Grade 4 Reading: 45 percent
• Grade 8 Math: 42 percent
• Grade 8 Reading: 44 percent

Average percent of students at or above proficient: 44.3 percent

Percent of students at or above proficient in:

• Grade 4 Math: 47 percent
• Grade 4 Reading: 43 percent
• Grade 8 Math: 46 percent
• Grade 8 Reading: 41 percent

Average percent of students at or above proficient: 45 percent

Percent of students at or above proficient in:

• Grade 4 Math: 53 percent
• Grade 4 Reading: 39 percent
• Grade 8 Math: 48 percent
• Grade 8 Reading: 40 percent

Average percent of students at or above proficient: 47 percent

Percent of students at or above proficient in:

• Grade 4 Math: 51 percent
• Grade 4 Reading: 46 percent
• Grade 8 Math: 46 percent
• Grade 8 Reading: 45 percent

Average percent of students at or above proficient: 50.3 percent

Percent of students at or above proficient in:

• Grade 4 Math: 54 percent
• Grade 4 Reading: 50 percent
• Grade 8 Math: 51 percent
• Grade 8 Reading: 46 percent