Interval

An interval is a level of measurement whereby the numeric values of the variable are equidistant and have intrinsic meaning. A classic example is income measured in dollars. An income score of $90,000 is immediately understood. Furthermore, the distance between someone with a $90,000 income and someone with a $90,001 income (i.e., one dollar) is equal to the distance between someone with a $56,545 income and someone with a $56,546 income (i.e., one dollar). Interval level of MEASUREMENT allows a high degree of precision and the ready use of MULTIVARIATE statistics. Interval measures are sometimes called QUANTITATIVE, or METRIC, measures. DATA that are interval can be converted to lower levels of measurement, such as ORDINAL or NOMINAL, but information is lost.