The non-structural techniques for attitude measurement are primarily of value in exploratory studies where the researcher is looking for the salient attributes of given products and the important factors surrounding purchase decisions as seen by the consumer. Structural techniques can provide a core objective measurement system, one which is more comparable to a scale or a yardstick. The term scaling has been applied to the efforts to measure attitudes objectively and a number of useful scales have been developed.
Ordinal scales are the simplest attitude measuring scales used in marketing research. They serve to rank respondents according to some characteristic such as favorability towards a certain brand, or to rank items such as brands in order of consumer preference. Such scales make no attempt to measure the degree of favorability of the different ratings. All the scales tell is that the individual or item has more or less the same amount of the characteristic being measured as some other item. This is the most widely used type of scale in marketing research.
Interval scales not only separate individuals or items by rank order but measure the distance between rank positions in equal units. Such a scale permits the researcher to say that position 4 on the scale is above position 3, and also that the distance from 5 to 4 is the same as the distance from 4 to 3. Such a scale, however, does not permit conclusions that position 6 is twice strong as position 3 because no zero position has been established.
If one measures the distance between two points as four feet and between two other points as two feet, it is possible to say that the one distance is twice that of the other because each distance is measured from an absolute zero. A scale that permits such measurements is called a ratio scale. While ratio scales are common in physical science, the measurement of attitudes is still so crude that they are of little significance in marketing research although efforts to develop attitude measurement scales that approximate ratio scales are having some success.
For practical purposes the ordinal scale is the only type with extensive use in marketing research. There is a growing tendency to treat many ordinal scales as if they are interval scales, and tests show this is a reasonable assumption in many cases. The degree of association between the simplest ordinal scale, rank ordering, and an interval scale has been shown to be quite high. There appears to be little loss in accuracy and considerable gain in interpretability if ordinal data are treated as interval data.
The most common variations of attitudes scales used in marketing research are described below. They are all basically ordinal scales, but the reader will note varying degrees of effort to make the distance between the various levels of the scale appear equal and thus approximate an interval scale. A simple ordinal scale is the rating scale in which respondents classify themselves a product or a concept in one of two categories. This may result from a dichotomous question, such as: Do you like or dislike television commercials? In answering this question, respondents classify themselves in one of two categories those who like television commercials and those who do not. A possible third category would include those who refuse to take position saying they neither like nor dislike commercials.
To simplify the process of the respondents, these alternatives may be specified so that they can check the ones that describe themselves. A further refinement is to provide additional alternatives in the form of degrees of liking or disliking and listing them in sequence so that the alternatives form a type of scale. Three variations of such self rating scales are the graphic rating scale, the ranking process, and multiple item scales.