Scaled Scores and Standard Score

Scaled Score:

Performance on each subtest results in a scaled score.

Standard Score:

A standard score is derived from raw scores using the norming information. Standard scores indicate how far above or below the average (the "mean") an individual score falls.

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Percentile

A percentile is a score that indicates the rank of the student compared to others (same age or same grade), using a hypothetical group of 100 students. A percentile of 35, for example, indicates that the student's test performance equals or exceeds 35 out of 100 students on the same measure

Confidence Intervals

Since an individual's performance on a test can vary on any given day, the confidence interval is the hypothetical range of scores predicted if that individual were given this test 100 times. 

Base Rate

Base rate is the naturally occurring frequency of a phenomenon in a population.

It is different from statistical significant, which tells us whether scores differ from what would be expected on the basis of chance alone.

Base rate is in fact more practical as it takes the probability-of-occurrence approach. A low base rate shows that an occurrence is not usual.