What is SEM?
The standard error of measurement (SEM) is a statistical phenomenon and is unrelated to the accuracy of scoring. All test results, including scores on tests and quizzes designed by classroom teachers, are subject to the standard error of measurement.

If a student were to take the same test repeatedly, with no change in his level of knowledge and preparation, it is possible that some of the resulting scores would be slightly higher or slightly lower than the score that precisely reflects the student’s actual level of knowledge and ability. The difference between a student’s actual score and his highest or lowest hypothetical score is known as the standard error of measurement.

False Negative Because of the standard error of measurement, the potential exists that a small percentage of students may score lower than anticipated on a test, given their level of knowledge and preparation. Testing experts refer to this phenomenon as a “false negative.”

False Positive Conversely, the possibility exists that a small percentage of students may score higher than otherwise would have been expected. Testing experts refer to this phenomenon as a “false positive.”

Test Retakes
Virginia accounts for the standard error of measurement on Standards of Learning (SOL) tests by allowing students unlimited retakes of tests needed for credit toward graduation. Students who score within 25 points of passing an SOL test qualify for an expedited retake. Students who score within 25 points of passing SOL tests in history/social studies and science also may receive a locally-awarded verified unit of credit.

Find the Standard Error of Measurement for Specific Tests
The standard error of measurement varies from test to test. On this page you will find links to tables displaying the standard errors of measurement associated with the threshold scores set by the Board of Education for proficiency (passing) and advanced proficiency on SOL tests administered in grade 8 and in high school. The information is displayed in the following manner:

Grade 8 Science	Core 1
Raw Score	Scale Score	SEM	Scale Score – 1 SEM	Scale Score + 1 SEM
30	403	15	388	418

Here is an explanation of the meaning of the above table:
A student who correctly answered 30 of the 60 questions on Core 1 of the fall, 2003 Grade 8 Science test had a scale score of 403. The standard error of measurement (SEM) at this particular point was 15 scale score units.

To view the standard error of measurement that relates to a student’s score on a particular test, select a test from the list below and then find the score. (Please see the current Virginia SOL Assessment Technical Report for updated and complete standard error of measurements.)