IQ score ranges group nearby scores into broad intervals. They can make a report easier to read, but their labels depend on the assessment. A boundary between two bands is not a sharp boundary between two kinds of person.
Read the scale first
For a reference scale with mean 100 and standard deviation 15, the following intervals have straightforward mathematical meanings. They are not diagnostic categories or starp classifications.
| Reference interval | Distance from 100 |
|---|---|
| 85 to 115 | Within one standard deviation |
| 70 to 130 | Within two standard deviations |
| 55 to 145 | Within three standard deviations |
Whether a particular test follows this model must be checked in its documentation. The same-looking numbers can come from different scoring systems.
Why a one-point boundary deserves caution
Suppose a report uses a label below 110 and a different label at 110. Scores of 109 and 110 are still adjacent values. The change in wording is a reporting choice; it does not establish a sudden difference in capability.
Where a test provides an appropriate confidence interval, read that alongside the score. Do not create your own error band by copying a margin from an unrelated assessment.
Score ranges on starp
starp currently converts the number of correct answers into values from 42 to 144. For example, 20 correct gives 90, 22 gives 100 and 24 gives 109. These are positions in starp's calibrated scoring table.
The four-skill profile adds a different view: the percentage of questions answered correctly in each domain. It is usually more actionable for practice than attaching an elaborate personality description to a score band.
Avoid turning a band into a prediction
A range does not tell you which career to choose, how much someone will earn or whether a person can master a subject. Use the test's actual evidence for its stated purpose. When a formal assessment is required, interpretation belongs with the qualified professional and the documentation for that assessment.