The Effect of Intensity of Effort to Reach Survey Respondents: A Toronto Smoking Survey

The number of calls in a telephone survey is used as an indicator of how difficult an intended respondent is to reach. This permits a probabilistic division of the nonrespondents into nonsusceptibles (those who will always refuse to respond), and the susceptible nonrespondents (those who were not available to respond) in a model of the nonresponse. Further, it permits stochastic estimation of the views of the latter group and an evaluation of whether the nonresponse is ignorable for inference about the dependent variable. These ideas are implemented on the data from a survey in Metropolitan Toronto of attitudes toward smoking in the workplace. Using a Bayesian model, the posterior distribution of the model parameters is sampled by Markov Chain Monte Carlo methods. The results reveal that the nonresponse is not ignorable and those who do not respond are twice as likely to favor unrestricted smoking in the workplace as are those who do.