Brief Version of Caffeine Expectancy Questionnaire in Brazil

Area of Science:

• Psychology
• Nutritional Science
• Psychometrics

Background:

• Extensive questionnaires can suffer from time-related biases, impacting data accuracy.
• A need exists for concise instruments to assess caffeine expectancies efficiently.
• The original Caffeine Expectancy Questionnaire (CaffEQ-BR) required a shorter version for practical use.

Purpose of the Study:

• To develop and validate a brief version of the Caffeine Expectancy Questionnaire in Brazil (B-CaffEQ-BR).
• To ensure the brief version possesses adequate consistency and reproducibility comparable to the full-length questionnaire.
• To create a psychometrically sound instrument suitable for caffeine expectancy research within the Brazilian adult population.

Main Methods:

• Statistical modeling was employed using the full CaffEQ-BR database to identify potential items for the brief version.
• An expert panel (n=3) blind-evaluated the semantic structure of selected items.
• The brief version (B-CaffEQ-BR) underwent reliability testing, including internal consistency (Cronbach's alpha) and interobserver reproducibility (Intraclass Correlation Coefficient - ICC) in Brazilian adults (n=62).

Main Results:

• The brief Caffeine Expectancy Questionnaire in Brazil (B-CaffEQ-BR) consists of 21 items across seven factors.
• The B-CaffEQ-BR demonstrated excellent internal consistency (Cronbach's α ≥ 0.729) and overall reproducibility (ICC ≥ 0.915).
• Statistical modeling achieved a Mean Absolute Error (MAE) below 0.5, and reliability metrics (Cronbach's α, ICC) met or exceeded the target of 0.7.

Conclusions:

• The brief Caffeine Expectancy Questionnaire in Brazil (B-CaffEQ-BR) is a reliable and valid instrument.
• Its psychometric properties are comparable to the full version, making it suitable for research.
• The B-CaffEQ-BR offers a valuable, time-efficient tool for studying caffeine expectancies in Brazilian adults.