Scale Classification Bases
The Scale Classification Bases can be categorized on the following bases.
- Subject orientation: In this, a scale is designed to measure the characteristics of the respondent who completes it or to estimate the stimulus object that is presented to the respondent.
- Response form: In this, the scales can be classified as categorical or comparative. Categorical scales (rating scales) are used when a respondent scores some object without direct reference to other objects. Comparative scales (ranking scales) are used when the respondent is asked to compare two or more objects.
- Degree of subjectivity: In this, the scale data is based on whether we measure subjective personal preferences or just make non-preference judgements. In the former case, the respondent is asked to select which person or solution he favors to be employed, whereas in the latter case he is simply asked to judge which person or solution will be more effective without reflecting any personal preference.
- Scale properties: In this, the scales can be classified as nominal, ordinal, interval and ratio scales. Nominal scales merely classify without indicating order, distance or unique origin. Ordinal scales indicate magnitude relationships of ‘more than’ or ‘less than’, but indicate no distance or unique origin. Interval scales have both order and distance values, but no unique origin. Whereas, ratio scales possess all these features.
- Number of dimensions: In this, the scales are classified as ‘uni-dimensional’ or ‘multi-dimensional’. In the former, only one attribute of the respondent or object is measured, whereas multi-dimensional scaling recognizes that an object might be described better by using the concept of an attribute space of ‘n’ dimensions, rather than a single-dimension continuum.
- Scale construction techniques: This can be developed by the following five techniques.
- Arbitrary approach: In this, the scales are developed on ad hoc basis. It is the most widely used approach.
- Consensus approach: In this, a panel of judges evaluates the items chosen for inclusion in the instrument regarding whether they are relevant to the topic area and unambiguous in implication.
- Item analysis approach: In this, a number of individual items are developed into a test that is given to a group of respondents. Post administering the test, total scores are evaluated, and the individual items are analyzed to determine which items discriminate between persons or objects with high and low total scores.
- Cumulative scales: These are chosen on the basis of their conforming to some ranking of items with ascending and descending discriminating power.
- Factor scales: This can be constructed on the basis of inter-correlations of items indicating a common factor accounts for the relationship between items.