Types advantages and dis advantages of Rating Scales

Numerical Rating Scales:
A sequence of numbers is assigned to descriptive Categories; the rater marks a number to indicate the degree to which a characteristic is present
Graphic Rating Scales:
A set of categories described at certain points along the line of a continuum; the rater can mark his or her judgment at any location on the line

Advantages of Rating Scales:  Used for behaviours not easily measured by other means  Quick and easy to complete  User can apply knowledge about the child from other times  Minimum of training required  Easy to design using consistent descriptors (e.g., always, sometimes, rarely, or never)  Can describe the child’s steps toward understanding or mastery
(b) Disadvantages
 Highly subjective (rater error and bias are a common problem).
 Raters may rate a child on the basis of their previous interactions or on an emotional, rather than an objective, basis.
 Ambiguous terms make them unreliable: raters are likely to mark characteristics by using different interpretations of the ratings (e.g., do they all agree on what “sometimes” means?).