Examining the validity of the drivers of COVID-19 vaccination acceptance scale using Rasch analysis

Background To well control the pandemic of COVID-19, herd immunity should be achieved. However, people, especially those with better physical conditions (e.g., young adults), may not accept COVID-19 vaccines. Understanding university students' willingness or reluctance to uptake COVID-19 vaccination is important. Aim This study aimed to examine the psychometric properties of the DrVac-COVID19S, an instrument that helps assess motivations/drivers of COVID-19 vaccination uptake among university students. Research design and methods Using convenience sampling and cross-sectional design, university students (930 from Taiwan [38.0% males] and 1,244 from Ghana [63.3% males]) completed the DrVac-COVID19S using an online survey (Taiwanese students) or paper-and-pen method (Ghanaian students). Rasch analysis was used to examine the psychometric properties of the DrVac-COVID19S. Results All 12 items in the DrVac-COVID19S had a satisfactory fit in the Rasch models (infit MnSq=0.74 to 1.49; outfit MnSq=0.72 to 1.42). Moreover, the seven-point Likert scale used in the DrVac-COVID19S demonstrated monotonically increasing in their difficulties, which indicated the ordered category. Additionally, no differential item functioning was displayed in the DrVacCOVID-19S across Taiwanese and Ghanaian students. Conclusions The DrVacCOVID-19S has good psychometric features to help healthcare providers assess individuals' (especially university students) motivations or drivers to get the COVID-19 vaccination.