Reducing ceiling effects in the Working Alliance Inventory-Rehabilitation Dutch Version

Purpose:To reduce ceiling effects on domain scores (Task, Goal, and Bond) of the Working Alliance Inventory (WAI)-Rehabilitation Dutch Version by changing response scales and using Visual Analogue Scales (VASs). Methods:Clients, who had at least three treatment sessions prior, randomly received one of the three versions of the WAI-Rehabilitation Dutch Version, using items with a balanced Likert scale, Positive-Packed Likert scale or VAS. Primary outcome was percentage of ceiling effects in total- and domain scores, secondary outcomes were construct validity and internal consistency of the three versions. Results:One hundred and seventy-six clients randomly received a set of questionnaires (one of the three versions of the WAI-Rehabilitation Dutch Version, Session Rating Scale (SRS) and Helping Alliance Questionnaire (HAQ)-II); 152 participants (mean age 51.5 +/- 16.3, 106 women) returned the questionnaires. No ceiling effects were present in the total scores of all versions. Significantly fewer ceiling effects were found in the VAS-Version (Goal: 8.0%, Bond: 7.7%) compared to the original (Goal: 18.0%, Bond: 29.8%) and Positive-Packed Version (Goal: 27.1%, Bond: 29.8%). Spearman's correlations between VAS-Version, SRS and HAQ-II ranged 0.747-0.845. Conclusions:Visual Analogue Scales effectively reduced ceiling effects on domain scores of the WAI-Rehabilitation Dutch Version, while maintaining validity.