I have been asked to analyze data from a large (n=402) study of an intervention for adolescents. One of the measures, that is quite highly used, is the CAFAS, which assesses functioning in children and youth, age 6 to 18. There are eight items, scored from 0 to 30 in increments of 10 (i.e., 0, 10, 20, 30). The eight items produce a total score ranging from 0 to 240. A review of the literature does not reveal really good reliability, either alpha, or ICC (the measure is clinician-completed). Item-total correlations range from .20 to .57. The distribution of scores on all items is skewed, either positively or negatively. I'm proposing to analyze each of the scales as if they were ordinal and the total score as interval, using a repeated measures approach since there are multiple measures per youth. I neither designed the study nor chose the measures. I've simply been commissioned to analyze the data. Any thoughts on treating the items as ordinal? I know it's conservative, but I have difficulty with a four-point discontinuous scale as really interval in nature.
| Free forum by Nabble | Edit this page |