measurement and scaling

Chapter 8

Measurement is the assignment of numbers or other symbols to characteristics of objects according to set rules. Scaling and involves the generation of a continuum upon which measured objects are located.

The four primary skills of measurement are:

1. nominal
2. ordinal
3. interval
4. ratio

Of these, the nominal scale is the most basic and that the numbers are used only for identifying or classifying objects. In the ordinal scale, the next higher level scale, the numbers indicate the relative position of the objects but not the magnitude of difference between them. The interval scale permits a comparison of the differences between the objects. However, as it has an arbitrary zero point, it is not meaningful to calculate ratios of scale values on an interval scale. The highest level of measurement is represented by the ratio scale in which the zero point is fixed. The researcher can compute ratios of scale values using the scale. The ratio scale it incorporates all the properties of the lower level scales.

Scaling techniques can be classified as comparative or non-comparative. Comparative scaling and involves a direct comparison of stimulus objects.

Comparative scales include:

• paired comparisons
• rank order
• constant sum
• Q-sort properties

Respondents in many developed countries, due to higher education and consumer sophistication levels, are quite used to providing responses on interval and ratio scales. However, in developing countries, preferences can be best measured by using ordinal scales. Ethical considerations require that the appropriate type of skills be used in order to get the data needed to answer the research questions and test the hypotheses. The Internet, as well as several specialized computer programs, are unavailable to implement the different types of scales.

Measurement -- the assignment of numbers or other symbols to characteristics of objects according to certain pre-specified rules
scaling -- the generation of a continuum upon which measured objects are located
nominal scale -- a scale whose numbers serve only as labels or tags for identifying and classifying objects with a strict one-to-one correspondence between the numbers in the objects
ordinal scale -- a ranking scale in which numbers are assigned to objects to indicate the relative extent to which some characteristic is possessed. Thus it is possible to determine whether an object has more or less of a characteristic and some other object
interval scale -- a scale in which the numbers are used to great objects such numerically equal distances on the scale represent equal distances in the characteristic being measured
ratio scale -- the highest scale. It allows the researcher to identify or classify objects, rank order the objects, and compare intervals or differences. It is also meaningful to compute ratios of scale values
comparative scales -- 1 or two types of scaling techniques in which there is direct comparison of stimulus objects with one another
non-comparative scales -- 1 of two types of scaling techniques in which each stimulus object is scaled independently of the other objects in the stimulus that
paired comparisons scaling -- a comparative scaling technique in which he respond it is presented with two objects at a time and asked to select one object in the pair according to some criterion. the data obtained are ordinal in nature
transitivity of preference -- an assumption made in order to convert paired comparison data to rank order data
rank order scaling -- a comparative scaling technique in which respondents are presented with several objects simultaneously and asked to order or rank them according to some criterion
constant sum scaling -- a comparative scaling technique in which respondents are required to allocate a constant sum of the units such as points, dollars, stickers, or chips among a set of stimulus objects with respect to some criterion
Q-sort scaling -- a comparative scaling technique that uses a rank order procedure to sort objects based on similarity with respect to some criterion