Background: Electronic cigarettes (e-cigarettes) are gaining in popularity as a new generation of flavored tobacco products replace combustible cigarettes. Increasing research is being conducted on e-cigarettes and its use to address this new important public health concern. Although great variations of instruments assessing e-cigarette use and its related constructs have been used, limited understanding related to psychometric properties of these instruments exist. The aims of the present systematic review are to provide an overview of current instruments used to measure e-cigarette related constructs and to examine methodological issues and psychometric properties such as reliability and validity of included instruments.

Methods: A systematic search process was utilized to retrieve articles from major search engines, including PubMed, Medline, CINAHL, EMBASE, PsycINFO, and Web of Science, using multiple key search terms. Empirical studies published in peer-reviewed journals that measured e-cigarette-related constructs were included. Following screening for eligibility, 22 articles were included for the final analysis. Item development, validation process, and psychological properties of each instrument were extracted for data analysis.

Results: Twenty-two instruments measuring e-cigarette-related constructs, including perceptions about e-cigarette risks, outcome expectations, susceptibility, motivations for use, dependence, and perceived harms were identified. Only five instruments were developed based on theoretical frameworks. Three instruments were validated for adolescents, and six included young adults. Reliability (i.e., Cronbach alpha) was reported for less than half of the studies (n=9). Most studies tested construct validity, and few tested predictive validity and criterion validity.

Conclusions: This systematic review provides a critical appraisal and repository of instruments measuring e-cigarette-related constructs in current literature. It provides insightful knowledge on gaps in e-cigarette-related research and suggests the need for developing valid and reliable instruments for various sub-populations.