Using Social Networks to Supplement RDD Telephone Surveys to Oversample Hard-to-Reach Populations: A New RDD+RDS Approach

Random digit dialing (RDD) telephone sampling, although experiencing declining response rates, remains one of the most accurate and cost-effective data collection methods for generating national population-based estimates. Such methods, however, are inefficient when sampling hard-to-reach populations because the costs of recruiting sufficient sample sizes to produce reliable estimates tend to be cost prohibitive. The authors implemented a novel respondent-driven sampling (RDS) approach to oversample cigarette smokers and lesbian, gay, bisexual, and transgender (LGBT) people. The new methodology selects RDS referrals or seeds from a probability-based RDD sampling frame and treats the social networks as clusters in the weighting and analysis, thus eliminating the intricate assumptions of RDS. The authors refer to this approach as RDD+RDS. In 2016 and 2017, a telephone survey was conducted on tobacco-related topics with a national sample of 4,208 U.S. adults, as well as 756 referral-based respondents. The RDD+RDS estimates were comparable with stand-alone RDD estimates, suggesting that the addition of RDS responses from social networks improved the precision of the estimates without introducing significant bias. The authors also conducted an experiment to determine whether the number of recruits would vary on the basis of how the RDS recruitment question specified the recruitment population (closeness of relationship, time since last contact, and LGBT vs. tobacco user), and significant differences were found in the number of referrals provided on the basis of question wording. The RDD+RDS sampling approach, as an adaptation of standard RDD methodology, is a practical tool for survey methodologists that provides an efficient strategy for oversampling rare or elusive populations

Product attributes affecting consumer preference for residential deck materials

In many countries, restrictions on the use of traditional preservative treatments have resulted in efforts to develop wood products for outdoor use that are durable, environmentally friendly, and appealing to consumers. In the present study, consumers’ preferences for wooden deck materials were investigated using sensory analysis. The analysis included an analytical sensory profiling of five deck materials, conducted by a trained sensory panel, as well as a hedonic preference study conducted on Norwegian customers. Eighteen visual and tactile attributes were identified, and statistical analysis indicated that these attributes were sufficient to discriminate between the different deck materials. The results imply that consumers prefer deck materials with a homogeneous visual appearance and moderate color intensity. The study demonstrated a successful application of sensory research on wood products and implies that sensory analysis is an appropriate tool to study relationships between hedonic judgments and product characteristics. The study was carried out on wooden deck materials, but the results are probably also relevant for other wood products

Prevalence of coronary heart disease risk factors in physical education students

Abstract To establish the prevalence of coronary risk in physical education students, and compare risk between the genders and the years of course. We evaluated 246 physical education students using RISKO questionnaire to determine eight risk factors: age, heredity, body weight, smoking, physical inactivity, hypercholesterolemia, hypertension and sex. Students had mean coronary risk score of 16.03 ± 3.52 points, rated "below-average risk." Men had significantly greater risk compared to women. No difference was found between the years of course. The prevalence of risk factors were heritability (58.37%), physical inactivity (32.65%), hypercholesterolemia (32.24%), overweight (27.35%), smoking (3.67%) and hypertension (2.45%). The coronary risk of physical education students was rated as below average, being higher among men than women, and no difference in risk between years of course. The most prevalent risk factors were heredity, physical inactivity, overweight and hypercholesterolemia