Results. To determine the construct validity of the developed scale in Study 1 and replicate the scale-testing, we:
1. Used an 80-20 split validation on the original dataset of Study 1. With this specific combination, the developed scale resulted in an acceptable model fit for 80% (TLI = 0.975, CFI = 0.985, RMSEA = 0.081) and 20% of the data (TLI = 0.975, CFI = 0.985, RMSEA = 0.080).
2. Used the dataset obtained from the validation in Study 2. With this dataset, the developed model resulted in an acceptable fit (TLI = 0.984, CFI = 0.990, RMSEA = 0.071).
We developed and validated a perceived persuasiveness scale to be used when conducting studies on digital behaviour interventions which didn’t exist. We conducted two studies in different domains to develop and validate this scale, namely in the healthy eating domain and the email security domain. The validated scale has 3 factors (Effectiveness, Quality, and Capability) and 9 scale items. The validated scale developed in this work can be used to improve such studies and will make it easier to compare the results of different studies and in different domains. We plan to use the scale to study the impact of message personalization across domains.
The work presented in this paper has several limitations. Firstly, we validated the scale in two domains (healthy eating and email security), and this validation needs to be extended to more domains. Secondly, the scale reliability needs to be verified. To investigate this, we need to perform a test-retest experiment in which participants complete the same scale on the same items twice, with an interval of several days between the two measurements. This also would need to be done in multiple domains. Thirdly, we need to repeat our studies into the impact message types with more messages and in more domains.