The main goal of the study was to develop and validate the Online Formative Assessment Validity Scale (OFAVS) within an English as a Foreign Language (EFL) environment. The scale was created based on a review of formative assessment literature and expert input, followed by item development, expert validation, pilot testing, and statistical validation. Data were collected from 316 Iranian EFL teachers through both online and printed formats. It also examined how the age and workplace of EFL teachers might influence their perceptions of OFA validity-related practices. According to Maleki et al. [37], the researchers developed a scale featuring important validity indicators tailored for formative assessments in EFL contexts. The final scale included 27 indicators grouped into four fundamental dimensions: authenticity of online assessment activities; effective online formative feedback; multidimensional perspectives towards online formative assessment; and online learner support. This study used two statistical analyses to analyze the data: Confirmatory Factor Analysis (CFA) and ANOVA. The CFA results indicated a moderate model fit (RMSEA = 0.086, CMIN/df = 3.32, CFI = 0.799), and the final 27-item version demonstrated high internal consistency (Cronbach’s alpha = 0.928). Moreover, the results revealed that the age and workplace of EFL teachers influenced their perceptions of practices associated with the validity of online formative assessments. These findings provide a validated measurement tool that can be used in both research and practice to assess perceptions of OFA validity. The study highlights the need to consider demographic and contextual variables when implementing online formative assessment strategies in EFL education, offering implications for teacher training and policy development.
