Scales of Measurement

This week, you were introduced to four scales of measurement, easily remembered with the acronym NOIR, and include:

• Nominal.
• Ordinal.
• Interval.
• Ratio.

Each of these levels or scales of measurement has its own properties, methods for assigning numbers or scores, and procedures for statistically manipulating them. As noted in your Psychological Testing and Assessment text, and adhering to a fundamentalist view of measurement statistics, all possible attributes in psychology can be examined through at least one of these four scales and the creation of scores that purport to measure them.

You also read about two methods for evaluating those scores by comparing them to a reference set of datanamely, norm-referenced testing and assessment and criterion-referenced testing and assessment. Each of these methods is unique in the focus regarding a test's scores or results.

In your discussion post for this week, follow the guidelines below:

Part I: Scales of Measurement and Referencing

• Provide at least one example of a psychological construct or attribute that can be measured in your specialization or a related profession for each scale of measurement (nominal, ordinal, interval, and ratio) that is not in your Psychological Testing and Assessment text.
• Provide at least one example of a psychological construct or attribute that can be measured in your specialization for each type of referencing (norm-referenced and criterion-referenced).
• Provide a statement that evaluates which scale of measurement appears to be the most useful for examining attributes in your specialization or a related profession. Explain why it is the most useful.
• Evaluate which method of referencing (norm or criterion) appears to be the most useful for examining attributes in your specialization or a related profession. Explain your decision based on the area of focus regarding the test results. For example, identify if it is preferable to focus on how one individual performs relative to others who took the same test, or if it is preferable to only focus on what the individual can or cannot do.

Part II: Norms

• Explain the different types of norms and the sampling procedures used when developing norms for a standardized test.
• Identify one use and one limitation for each type of norm.