Validity of a streamlined version of the Focus on the Outcomes of Communication Under Six: Process and outcome

Background The Focus on the Outcomes of Communication Under Six (FOCUS) is a 50-item outcome measure based on the framework and concepts of World Health Organization's International Classification of Functioning. The FOCUS has been shown to capture participation-level changes associated with speech and language therapy in children 18 to 72 months old and has established validity and reliability. However, there were reasons to try to reduce the measure without losing any of its proven value as a change-detecting instrument. Methods Using data from 18,931 preschool children, we used item response models and a test of redundancy to reduce the original 50-item FOCUS to 34 items. We then assessed the correlations between FOCUS-50 and FOCUS-34 scores on these children. Results Findings show that a shortened (34-item) version of FOCUS can be treated as equivalent to the full 50-item version. Conclusion The correlation between change scores on the two versions is .98. We suggest that in situations where only a total score is of interest, the FOCUS-34 can be used in place of the full FOCUS.