5.2 levels of measurement

Levels of Measurement Overview

• Definition: Different levels of quantitative information communicated through scores, involving categories and assignment procedures.

Nominal Level

• Definition: Qualitative categories without order.

• Example: College students grouped by major.

Ordinal Level

• Definition: Named categories that can be ranked.

• Example: Shirt sizes (XS to XL).

Interval Level

• Definition: Sequential categories with equal size but arbitrary zero.

• Example: Time of day events occur.

Ratio Level

• Definition: Ordered categories with equal size and an absolute zero.

• Example: Fuel amount in a vehicle.

Summary of Measurement Levels

• Nominal: No order.

• Ordinal: Rank-ordered.

• Interval: Rank-ordered with equal differences.

• Ratio: Rank-ordered, equal differences, absolute zero.

Statistical Considerations

• Interval/Ratio Scores: Suitable for arithmetic operations and statistical analysis.

• Ordinal Scores: Not suitable for basic arithmetic.

Scale Comparison Ability

• Nominal: Identifies differences.

• Ordinal: Indicates direction.

• Interval: Indicates direction and magnitude.

Choosing a Scale of Measure

• Questions:

  • Can a value be more than another?

  • Is the difference between values constant?

  • Can a value be zero?

Scale Type Summary