Details for measurement scales for data.

In order of desirability: Nominal – ordinal – interval – ratio.

Nominal Scale of Measurement

  • Data that consists of names or categories only.
  • Allows us to classify the object.
    • Ex. Is a famous beach or not.
  • Does not allow rank
    • Ex. Doesn’t rank HOW famous the beach is.
  • Cannot determine the interval.
  • No ordering scheme is possible.
  • Ex. # of M&M colors in a bag.

Ordinal (Ranking) Scale of Measurement

  • Data arranged in order.
  • Differences between the values cannot be determined or are meaningless.
  • A ranking scale.
  • Ex. Likert Customer satisfaction scale.
    • The difference between a 2 rating and a 4 rating does not mean the customer is twice as satisfied when giving a 4.
  • Ex. Software defect categories.
    • 3 UI, 4 data, 1 browser compatibility.
  • Ex. House of Quality roof example.

Interval Scale of Measurement

  • Has an interval.
  • Data is arranged in order and differences can be found.
  • No starting point.
  • Ratios are meaningless.
  • Ex. Temperature of 3 pizzas. if one pizza is 100 degrees, that doesn’t make a 300 degree object 3 times as hot.

Ratio Scale of Measurement

  • Extension of interval level that includes a zero starting point.
  • Data is high level variable data.
  • There is an inherent zero starting point.
  • Both differences and ratio are meaningful.
  • Classify objects
  • Rank objects
  • Has equal intervals
  • Has a true zero point
  • Ex. Watches that cost $200 and $400. The 2nd one is 2 times as expensive as the first.

Also see:


Comments (2)

the words on the graphs/pictures are hard to read. we can’t do the multiple choice questions or understand some content without being able to read those fine letters.

Hi Ming,

Thanks for the feedback. Let’s catch up in the members forum.

If you can tell me there which images / questions and what kind of device you’re using, I’ll get those updated immediately.

Best, Ted.

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