The aims of the research are to evaluate the factorial validity, internal consistency, measurement invariance, discrimination, and difficulty of the Covid-19 Anxiety Scale (CAS) applied to a sample of Ecuadorian adults ( N = 451). The study is based on an instrumental design with Classical Test Theory (CTT) and Item Response Theory (IRT) technics. The results confirmed the validity of the CAS single-factor structure, with measurement invariance across gender and high internal consistency. Additionally, all CAS items displayed adequate discrimination indexes and proper ordering of the difficulty thresholds. In a conclusion, the CAS is a valid measurement scale for Ecuadorian adults.

The most popular instrument used to measure emotional regulation is the Emotion Regulation Questionnaire (ERQ), allowing researchers to study intergroup differences in emotional regulation across many different cultures. However, to make multi-group comparisons, factors within the measurement instrument must be invariant across groups. This invariance is necessary to ensure that any significant differences found between groups are due to group affiliation and not due to measurement errors in the instrument’s factors. The study examined measurement invariance of the ERQ by gender using an Ecuadorian sample, where very few studies have previously investigated this issue. The sample included 815 college students. A confirmatory factor analysis indicated that the bi-factor model presented the best fit. The ERQ was invariant by gender at the strict level according to multi-group confirmatory factor analysis. The ERQ also presented good reliability scores for both men and women with no significant differences between genders. These results confirm that the ERQ is a reliable instrument and that it can detect differences in the use of emotional regulation strategies between men and women without risking errors caused by measurement variance.