Classification as Measurement

1. Classification as Measurement Measurement involves a logical continuity from qualitative classification to the more rigorous forms of measurement by way of intermediate devices of systematic ratings, ranking scales, multidimensional classifications, typologies and simple quantitative indices.

2. Some problems with the continuum of measurement procedures: • The formation of categories in terms of which the objects under study are classified or measured • Classification of items into given categories more systematic than personal judgment • The logic of multidimensional classification and their relation to typologies • Problems raised when we try to combine various observations in to quantitative indices

3. Formation of Categories • Forming the concept of a variable – what do we want to study? • When we have formed some such category, we may want to break it down into component elements upon which to base research instruments--instructions to coders, ranking scales, indicators; these in turn may be combined in multidimensional patterns, typologies or over-all indices • Usually faced with an array of raw data for which ready-made theoretical categories will not exist. • Example: • Why are people living in “transient housing”? • Opportunists – Necessitarians • How long do people who live in transient housing stay in one place? • Permanent – Temporary • Immediate problem is to get the raw data classified in some reasonable preliminary way so that it can be communicated, cross-tabulated and thought about

4. Requirements for a good classification system for free responses • Articulation • Logical Correctness • Adaptation to the Structure of the Situation • Adaptation to the Respondent’s Frame of Reference

5. Articulation The classification should proceed in steps from the general to the specific, so that the material can be examined either in terms of detailed categories or of broad groupings, whichever are more appropriate for a given purpose

6. Logical Correctness In an articulated set of categories those on each step must be mutually exclusive and exhaustive. When an object is classified at the same time form one than one aspect, each aspect must have its own separate set of categories

7. Adaptation to the Structure of the Situation The classification should be based on a comprehensive outline of the situation as a whole—an outline containing the main elements and processes in the situation which is important to distinguish for purposes of understanding, prediction, or policy-making

8. Adaptation to the Respondent’s Frame of Reference The classification should present as clearly as possible the respondent’s own definition of the situation—his/her focus of attention, categories of thought