The Japanese version of the reduced morningness-eveningness questionnaire

ABSTRACT

Circadian typology, or “morningness” and “eveningness,” is generally assessed using the Morningness-Eveningness Questionnaire (MEQ), a 19-item scale that could be burdensome in large-scale surveys. To overcome this, a 5-item version known as the reduced morningness-eveningness questionnaire (rMEQ), which is sensitive to the assessment of circadian typology, was developed; however, a validated Japanese version of the rMEQ is yet to be established. This study aimed to develop and validate the Japanese version of the rMEQ. Five essential items for the rMEQ were selected from existing Japanese MEQ data (N = 2,213), and the rMEQ was compiled. We conducted a confirmatory factor analysis for the psychometric properties of the rMEQ and confirmed its robust one-factor structure for evaluating morningness-eveningness (GFI = 0.984, AGFI = 0.951, CFI = 0.935, and RMSEA = 0.091). Reliability was evaluated via internal consistency of rMEQ items using Cronbach’s α and McDonald’s ω, and the values were 0.618 and 0.654, respectively. The rMEQ scores strongly correlated with MEQ (ρ = 0.883, p < 0.001), and classification agreement (Morning, Neither, and Evening types) between rMEQ and MEQ was 77.6% (Cramer’s V = 0.643, Weighted Cohen’s κ = 0.72), confirming the validity. The Japanese rMEQ may be a valuable tool for the efficient assessment of circadian typologies.

KEYWORDS:

• Circadian typology
• morningness
• eveningness
• rMEQ
• validation

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The datasets analyzed in this study are not publicly available because of the privacy policy but are available from the corresponding author upon reasonable request.

Additional information

Funding

This work was supported by JSPS KAKENHI Grant Number JP16H01655.