Scale or Index?

 

1 - Scale: a class of quantitative data measures often used in survey research that captures the intensity, direction, level or potency of a variable construct along a continuum; most are at the ordinal level of measurement

2 - Index: The summing or combining of many separate measures of a construct or variable to create a single score

Principles of good measurement

 

1 – Mutually exclusive attributes: every response is clearly different from others

2 – Exhaustive attribute: every response has a place to go

3 – Uni-dimensionality : only one construct is measured