Development and psychometric properties of the Smoking Restraint Questionnaire.

Restraint is a component of self-control that focuses on the deliberate reduction of an undesired behavior and is theorized to play a role in smoking reduction and cessation. However, there exists no instrument to assess smoking restraint. This research aimed to develop the Smoking Restraint Questionnaire (SRQ) to meet this need. Participants were 406 smokers (48% female; 52.2% nondaily) with a mean age of 38.83 years (SD = 12.05). They completed a baseline questionnaire designed to assess smoking restraint. They also completed 21 days of ecological momentary assessment (EMA), during which they recorded each cigarette smoked and answered questions related to planned restraint every morning, and restraint attempts every evening. The 4-item questionnaire of smoking restraint was found to fit a single factor (root mean square error of approximation = .038, comparative fit index = .99, Tucker-Lewis index = .99), and the resulting composite was reliable (composite reliability = 0.74). The questionnaire contains items that assess the setting of weekly restraint goals and attempts at not lighting up when tempted to smoke. Participant SRQ scores positively correlated with EMA data on plans to restrain (p < .001) and frequency of restraint attempts (p < .001). These correlations suggest that the SRQ has good predictive validity in relation to the intention and behaviors of smoking reduction. The SRQ is promising as a measure of smoking restraint and may enable further research and insights into smoking reduction and cessation.