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Developing and validating measures of absolute and relative e-cigarette product risk perceptions: Single items can be surprisingly comprehensive.

INTRODUCTION
Tobacco risk perceptions are important predictors of behavior and are impacted by tobacco communications. Our systematic literature review (completed in 2018) found there were no measures of e-cigarette risk perceptions that were completely consistent with tobacco researcher recommendations (e.g., specifying use frequency) and had demonstrated validity and reliability. The current study develops measures to assess specific risk perceptions, including absolute risks and risks compared to cigarettes, nicotine replacement therapy, and all nicotine cessation.


METHODS AND RESULTS
We generated a list of tobacco health effects based on our previous systematic review of tobacco risk perception measures. Based on health effects prioritized by regulatory science experts, we developed 63 items to assess seven types of e-cigarette risk perceptions: absolute health and addiction risks, health and addiction risks relative to cigarettes, pregnancy health risks relative to cigarettes, health risks relative to nicotine replacement therapy, and health risks relative to all nicotine cessation. We fielded these items in an online survey (N=1,642). Through reliability and validity analyses, we reduced this pool to 21 items, including many single-item measures. Supporting the measures' validity, each measure was negatively associated with current e-cigarette use, e-cigarette intentions, and skepticism about e-cigarette harms; and positively associated with perceiving e-cigarettes as equally or more harmful than cigarettes and intentions to quit e-cigarettes.


DISCUSSION
This study developed and validated brief measures of several types of e-cigarette risk perceptions. Surprisingly, we found that for many types of risk perceptions, multi-item measures were redundant and these perceptions were well-represented by single-item measures.


IMPLICATIONS
This study developed measures of seven types of e-cigarette health risk perceptions, including absolute health and addiction risk, and risk relative to cigarettes, nicotine replacement therapy, and cessation. We reduced 63 items to 21 to measure all of these constructs. These measures follow tobacco researcher recommendations, were developed using a rigorous measurement-development process, and demonstrated some aspects of reliability and validity. Because these measures are publicly available, they can be used by public health and industry researchers.