Scale construction techniques

Following are the five main techniques by which scales can be developed.

1.  Arbitrary approach: It is an approach where scale is developed on ad hoc basis. This is the most widely used approach. It is presumed that such scales measure the concepts for which they have been designed, although there is little evidence to support such an assumption.
2. Consensus approach: Here a panel of judges evaluates the items chosen for inclusion in the instrument in terms of whether they are relevant to the topic area and unambiguous in implication.
3. Item analysis approach: Under it a number of individual items are developed into a test which is given to a group of respondents. After administering the test, the total scores are calculated for everyone. Individual items are then analysed to determine which items discriminate between persons or objects with high total scores and those with low scores.
4. Cumulative scales are chosen on the basis of their conforming to some ranking of items with ascending and descending discriminating power. For instance, in such a scale the endorsement of an item representing an extreme position should also result in the endorsement of all items indicating a less extreme position.
5. Factor scales may be constructed on the basis of inter-correlations of items which indicate that a common factor accounts for the relationship between items. This relationship is typically measured through factor analysis method.