More of a narrative label than a particularly useful summary statistic though it is one: it’s the difference between the maximum and minimum observed values of a variable in a dataset, i.e. maximum minus minimum. It’s often used in a more narrative fashion: “the score range was 1.31 to 4.87” which isn’t strictly following the mathematical and statistical meaning of the word for which that should be ““the score range was 3.56”. We can’t remember ever seeing the word used that, technically correct, way in a therapy data report.

## Details #

Being technical, if the range is of a five level item score it’s probably going to be 4 if the dataset is large enough to have all the theoretically possible scores regardless of whether the item is scored 0 to 4 or 1 to 5. Technically it is, like the variance and standard deviation (SD), a measure if dispersion but it’s defined only by the two values of the observed minimum and maximum whereas variance and SD are defined by all the observed values.

#### Try also… #

Minimum

Maximum

Variance

Standard Deviation (SD)

Dispersion (“spread”)

Inter-quartile range