Convergent and Discriminant Validity Evidence of the Methodological Quality Scale for Studies Based on Observational Methodology (MQSOM)

The use of observational methodology has become increasingly more common in psychological research, highlighting the need for tools that ensure methodological rigor. This study presents evidence of convergent/discriminant validity for the Methodological Quality Scale for Studies Based on Observational Methodology (MQSOM). A multitrait-multimethod (MTMM) analysis with Spearman's correlations was used to examine the relationship between MQSOM dimensions and those of three instruments: the Methodological Rigor in Mixed Methods (MRMM), the Guidelines for Reporting Evaluations Based on Observational Methodology (GREOM), and the Mixed Methods Appraisal Tool (MMAT). Ninety-six articles were coded using MQSOM and the instruments for comparison. The MQSOM's design converged with the MRMM's mixed-methods design (ρ = .217, <i>p</i> = .034), GREOM's design (ρ = .217, <i>p</i> = .034), and MMAT's qualitative (QUAL) component (ρ = .212, <i>p</i> = .038). The MQSOM's measurement and analysis aligned with MRMM's data analysis (ρ = .611, <i>p</i> < .001), GREOM's data quality control (ρ = .423, <i>p</i> < .001) and results (ρ = .328, <i>p</i> = .001), and MMAT's quantitative (QUANT) (ρ = .214, <i>p</i> = .037) and mixed-methods (ρ = .643, <i>p</i> < .001) components. MQSOM's design exhibited discriminant validity from MRMM's data collection (ρ = .025, <i>p</i> = .807) and data analysis (ρ = -.051, <i>p</i> = .620), GREOM's data quality control (ρ = .025, <i>p</i> = .812) and results (ρ = -.032, <i>p</i> = .759), and MMAT's QUANT component (ρ = -.035, <i>p</i> = .733). This study reinforces the validity of MQSOM as a useful methodological quality scale.