Testing intensity of preference or scaling human response is about measuring the strength of people's opinions. To measure or rate something, however, you need a ruler first. Researchers build intensity scales based on how they want to measure a preference and how precisely or in depth they want it measured. A researcher could measure how much something is liked with a 1 for "Awful" to 5 for "Excellent" point scale or be more precise with a 1 to 10 point scale. Words must be attached to the scale for people to know what each point on it means. The scale is then applied to whatever the researcher wants to explore -- for example, to rate a car's overall performance, handling, interior comforts, or the likelihood the driver will return to the dealer for service. The number of measuring scales and words defining them are as infinite as the number of things our imagination finds to measure.
Word and number scales are common. Word scales use only words to develop a measuring scale. They can be a comparative system such as "Hot," "Hotter," "Hottest" or "Never," "Once," "Sometimes," "A Lot" or "Every Time". They can also be a positive and negative system such as a Likert scale. Used for decades in survey research, the Likert scale uses "Greatly Disagree," "Disagree," "Agree" and "Greatly Agree" as its measuring base.
A number scale asks the respondent to associate a number with the strength of her feelings. Generally, the higher or lower the number, the stronger the preference. Numerical scales use a word beside each or some numbers in the scale. They can also indicate good and bad feelings with positive and negative numbers. A restaurant survey question asking about service might look like this: "Slow," -3,-2,-1, "Fast," 1,2,3. Pictures with numbers, like a thermometer, are also used.
Polar scales start with two words or concepts meaning the opposite of each other with a number scale between them. For example, a question measuring how involved people are in their children's education may use "Not Involved at All 1-2-3-4-5 Very Involved" as a scale. People choose the number best representing how they feel. Polar scales are also used to assist in making allocation decisions. Human Resources might ask employees about how best to allocate a bonus with an "All Cash," "Split Cash and Holidays," "All Holidays"-type question. A government might ask the public about how to allocate a surplus with an "All Pay Down Deficit," "Split Deficit" and "Create Jobs" or "All Create Jobs"-type question.