Psychometric Evaluation and International Normative Data for the Megalophobia Severity Screening Scale (MSSS-20): A Cross-Cultural Validation Study

Megalophobia—the specific phobia characterized by an intense, irrational fear of large objects, structures, or vast environments—is relatively common, yet remains underrepresented in psychometric research. This study evaluates the psychometric properties, internal consistency, dimensional profile, and international norms of the Megalophobia Severity Screening Scale (MSSS-20), a 20-item multidimensional instrument designed to assess megalophobic symptoms across four subscales: Size Fear, Environmental Anxiety, Object Avoidance, and Visual Discomfort. Method: A cross-sectional sample of 351 participants across 37 countries completed the MSSS-20 through an online psychometric screening portal between June 11, 2026, and July 12, 2026. The sample was primarily represented by participants from India (29.9%), the United States (15.4%), and Germany (9.4%). Basic demographics (age and gender) were voluntarily recorded. Statistical evaluation involved descriptive analysis, internal consistency estimation (Cronbach's alpha), item-total correlation analysis, and percentile normative mapping. Results: The overall observed mean score was 50.92% (SD = 15, Median = 49, Variance = 224.89, SE = 0.8). Skewness (0.57) and kurtosis (0.51) fell within acceptable parameters for a normal distribution. The MSSS-20 demonstrated acceptable overall internal consistency (alpha = 0.713). Item-total correlations ranged from r = -0.02 to r = 0.52, with ten items performing weakly (r < 0.30), highlighting areas for future revision. Subscale analysis indicated the highest mean scores in the Size Fear dimension (59.59%) and the lowest in Visual Discomfort (44.72%).