Changes of knowledge, attitudes, beliefs, and preference of bar owner and staff in response to a smoke-free bar law.

OBJECTIVE: To examine attitudinal changes of bar owners and staff regarding a smoke-free bar law. DESIGN: Bar owners and staff were random selected and telephone interviewed in June 1998, shortly after a smoke-free bar law was enacted, and October 2002. Similar instruments were used in both surveys to collect data on attitudes related to secondhand smoke (SHS) and behaviours related to the smoke-free bar law. PARTICIPANTS: 651 and 650 respondents worked for either stand alone bars or combination bars. MEASURES: Preference of working in a smoke-free environment, concerns of the effect of SHS, and how to comply with the law. RESULTS: The percentage of bar owners or staff working in stand alone bars who prefer to work in a smoke-free environment increased from 17.3% in 1998 to 50.9% in 2002 (p < 0.001). Significantly more respondents (45.5%) working in stand alone bars were concerned about the effects of SHS on their health, comparing to 21.6% in 1998 (p < 0.001). When patrons smoked in the bar, 82.1% of stand alone bar owners or staff in the 2002 survey would ask them to stop or to smoke outside, increased from only 43.0% in the 1998 survey (p < 0.001). CONCLUSION: A positive and significant attitudinal change related to the smoke-free bar law occurred among California bars.

Improving the self reporting of tobacco use: results of a factorial experiment.

OBJECTIVES: To examine divergent estimates of smoking prevalence in two random digit dial surveys for the same population. Based upon internal and external reviews of survey procedures, differences in survey introductions (general health versus tobacco specific introduction) and/or differences in the use of filter questions were identified as the most likely explanations. This prompted an experiment designed to investigate these potential sources of measurement error. DESIGN: A randomised 2 x 2 factorial experiment. SETTING: A random digit dial telephone survey from July to September 2000. SUBJECTS: 3996 adult Californian respondents. MAIN OUTCOME MEASURES: A series of smoking prevalence questions in the context of a tobacco or general health survey. RESULTS: Logistic regression analyses suggest that, among females, prior knowledge (from the survey introduction) that a survey is concerned with tobacco use may decrease self reported smoking prevalence (approximately 4% absolute prevalence difference). Differences in the use of filter questions resulted in almost no misclassification of respondents. CONCLUSIONS: The tobacco specific survey introduction is causing some smokers to deny their tobacco use. The data suggest that these smokers tend to be women that smoked occasionally. A desire by the participants to minimise their personal time costs or a growing social disapproval of tobacco use in the USA may be contributing to the creation of previously undetected survey artefacts in the measurement of tobacco related behaviours.

Comparison of methods for estimation of individual-level prevalence based on pooled samples.

We review frequentist and Bayesian approaches for estimating animal-level disease prevalence using pooled samples obtained by simple random sampling. We determine the preferred approach for different prevalence scenarios and with varying knowledge about sensitivity and specificity values. When sensitivity and specificity are perfect or known, we can choose between the large-sample theory estimates and the one-to-one relationship exact estimates. When sensitivity and specificity are unknown, we must use large-sample theory estimates or Bayesian methodology (which gives exact estimates). However, when the large-sample theory produces a negative lower confidence limit, we must use one of the exact methods. We compare estimates from each approach using culture results from pools of 20 eggs from three flocks on a California ranch that were producing eggs that were contaminated with Salmonella enteritidis phage type 4.