SCALES OF MEASUREMENT

One key consideration in collecting data is using the appropriate level of measurement. There are four levels of measurement, and each possesses unique characteristics:

  • Nominal: essentially used to name
  • Ordinal: to convey rank order
  • Interval: to convey equal intervals in addition to conveying rank
  • Ratio: in addition to all the previous characteristics, involves an absolute zero point

Nominal and ordinal data are usually associated with qualitative data, and interval and ratio data are referred to as quantitative data. Table 10.1 illustrates the unique characteristics of each scale and gives examples of data for each.

TABLE 10.1. Scales of Measurement

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