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Objective Measurement of Subjective Phenomena

5. Items, Levels of Measurement, and Methods of Scale Construction

Items

Two general categories of items: Objective and non-objective items (McDonald, 1999). Objective items are those that involve no subjectivity when scoring responses. Conversely, non-objective (or subjective) items are items that leave some room for subjectivity in scoring. Given their preponderance in survey methodology, we concentrate here on objective items.

Types of objective items: Objective items come in many different forms, several of which are shown below (see McDonald, 1999), for a more extensive review of item types):

Completion items state a problem, and the respondent must generate an answer.

Example 17

Completion item example:

Example: 5 + 4 = ____

Multiple-choice items provide a question stem and several answer options; the test taker must select one (or more) of the options as the optimal answer.

Example 18

Multiple-choice item example:

The mean of a distribution is a measure of

  1. location
  2. standard deviation
  3. variance
  4. range

Ordered-category items allow respondents to register their response on a graded continuum, which is a very common approach to measuring many behavioral outcomes.

Example 19

Ordered-category item example:

Example depicting ordered-category items as discussed in the text.

Example 20

Ordered-category item example:

Example depicting ordered-category items as discussed in the text.

McDonald, R. P. (1999). Test theory: A unified treatment. Mahwah, NJ: Erlbaum.
McDonald, R. P. (1999). Test theory: A unified treatment. Mahwah, NJ: Erlbaum.