LSAT scores are estimates of a test taker’s actual proficiency in the skills tested.
LSAT scores are reported along with a score band because the estimate of proficiency provided by a given LSAT score is not perfectly accurate. A test taker’s actual proficiency in the skills tested on the LSAT may be slightly higher or slightly lower than that reflected by the score received on an officially administered LSAT.
The score band indicates a range of scores, including scores slightly higher and slightly lower than the score received. The test taker's actual proficiency in the skills measured is likely to fall within this range.
In other words, even though an individual score received on an officially administered LSAT is an estimate of a test taker’s actual proficiency in the skills tested, it is unlikely that the test taker’s actual proficiency in the skills tested is more than a few points higher or lower than the score received.
How the Score Band is Calculated
The LSAT, like any standardized test, is not a perfect measuring instrument. One way to quantify the amount of measurement error associated with LSAT scores is through the calculation of the standard error of measurement. The standard error of measurement provides an estimate of the average error that is present in test scores because of the imperfect nature of the test.
The standard error of measurement for the LSAT is very stable, and tends to be about 2.6 scaled score points. A score band with a 68 percent confidence level can be constructed by subtracting the standard error of measurement from the scaled score to obtain the lower value and adding the standard error of measurement to the scaled score to obtain the upper value. Therefore, the width of the score band is approximately 7 scaled-score points, after rounding.
The 68 percent (or approximately two out of three) level of confidence used by LSAC for reporting purposes is a commonly used standard. To obtain a 95 percent level of confidence, the standard error of measurement can be doubled before constructing the score band. Therefore, a 95 percent confidence band would be approximately twice as wide as a 68 percent confidence band.
LSAC employs a more complicated calculation to accommodate scores that lie at the upper and lower extremes of the LSAT score scale.
For test takers who take the test more than once, the standard error of measurement is calculated in a similar way as that described above. However, there is less measurement error associated with an average score than there is with a score earned on a single day of testing. The standard error of measurement is adjusted to take into account the number of scores earned by the candidate in calculating the score band for an average score, resulting in a somewhat narrower band.