BACKGROUND Often in survey research, subsets of the population invited to complete the survey do not respond in a timely manner and valuable resources are expended in recontact efforts. Various methods of improving response have been offered, such as reducing questionnaire length, offering incentives, and utilizing reminders; however, these methods can be costly. Utilizing characteristics of ea...

Research into the changes in the frequency of sexual intercourse is (with few exceptions) limited to cross-sectional analyses of marital duration. We investigate the frequency of intercourse while taking into account relationship duration as well as the duration of cohabitation and marriage, effects of parenthood, and relationship quality. For the analysis we apply fixed effects regression mode...

Evidence relating to dietary change is contradictory, as some studies document a lack of dietary change while other studies report a degree of success in the implementation and maintenance of long-term dietary change. The present cross-sectional survey aimed to establish the prevalence of dietary change in a community sample, with a focus on four mechanisms of dietary change: two mechanisms wit...

In Senegal, only 60% of mothers in rural areas deliver in health facilities. Mothers' satisfaction with their facility-based childbirth experience is one of the factors in their choosing to deliver in such facilities in subsequent pregnancies. The objective of this study was to assess whether compliance with childbirth care based on the mothers' perception of facility-based childbirth care cont...

Descriptive epidemiology research involves collecting data from large numbers of subjects. Obtaining these data requires approaches designed to achieve maximum participation or response rates among respondents possessing the desired information. We analyze participation and response rates in a population-based epidemiological study though a telephone survey and identify factors implicated in co...

BACKGROUND Lower socioeconomic position (SEP) is associated with an increased risk of suicidal behaviour in high-income countries, but this association is unclear in low-income and middle-income countries. METHODS We investigated the association of SEP with attempted suicide in a cross-sectional survey of 165 233 Sri Lankans. SEP data were collected at the household (assets, social standing (...

In the context of observational longitudinal studies, we explored the values of the number of participants and the number of repeated measurements that maximize the power to detect the hypothesized effect, given the total cost of the study. We considered two different models, one that assumes a transient effect of exposure and one that assumes a cumulative effect. Results were derived for a con...

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Whereas most research on usability focuses on known applications we explore the first encounters. Starting up new applications expectancy, impression management, initial dialogues and acquaintance, and ritualizing operations have to be handled. We present the research approach and document short histories of learning and fascination. Focussing on business users of mobile services we conducted d...