Development and equivalence of new faces for inclusion in the Childhood Asthma Control Test (C-ACT) response scale

BACKGROUND: Accurate symptom monitoring is vital when managing pediatric asthma, providing an opportunity to improve control and relieve associated burden. The CHILDHOOD ASTHMA CONTROL TEST (C-ACT) has been validated for asthma control assessment in children; however, there are concerns that response option images used in the C-ACT are not culturally universal and could be misinterpreted. This cross-sectional, qualitative study developed and evaluated alternative response option images using interviews with children with asthma aged 4–11 years (and their parents/caregivers) in the United States, Spain, Poland, and Argentina. Interviews were conducted in two stages (with expert input) to evaluate the appropriateness, understanding and qualitative equivalence of the alternative images (both on paper and electronically). This included comparing the new images with the original C-ACT response scale, to provide context for equivalence results. RESULTS: Alternative response option images included scale A (simple faces), scale B (circles of decreasing size), and scale C (squares of decreasing quantity). In Stage 1, most children logically ranked images using scales A, B and C (66.7%, 79.0% and 70.6%, respectively). However, some children ranked the images in scales B (26.7%) and C (58.3%) in reverse order. Slightly more children could interpret the images within the context of their asthma in scale B (68.4%) than A (55.6%) and C (47.5%). Based on Stage 1 results, experts recommended scales A (with slight modifications) and B be investigated further. In Stage 2, similar proportions of children logically ranked the images used in modified scales A (69.7%) and B (75.7%). However, a majority of children ranked the images in scale B in the reverse order (60.0%). Slightly more children were able to interpret the images in the context of their asthma using scale B (57.6%) than modified scale A (48.5%). Children and parents/caregivers preferred modified scale A over scale B (78.8% and 90.9%, respectively). Compared with the original C-ACT, most children selected the same response option on items using both scales, supporting equivalency. Following review of Stage 2 results, all five experts agreed modified scale A was the optimal response scale. CONCLUSIONS: This study developed alternative response option images for use in the C-ACT and provides qualitative evidence of the equivalency of these response options to the originals. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s41687-021-00390-2.