Chen H.,National Health Research Institute |
Huang X.,Pennsylvania State University |
Guo X.,Westat Inc |
Peddada S.,National Health Research Institute
Movement Disorders | Year: 2014
Background: Some nonmotor symptoms may precede the clinical diagnosis of Parkinson's disease (PD) by years. Methods: We examined the individual and joint prevalence of depression, daytime sleepiness, and infrequent bowel movement among 10,477 participants of the US National Health and Nutrition Examination Surveys 2005-2008. Results: For all symptoms, the prevalence was higher in women than in men. Importantly, few participants had two or more symptoms: 1.3% at ages 20 to 29, 1.0% at 30 to 39, 1.2% at 40 to 49, 3.5% at 50 to 59, 1.7% at 60 to 69, 1.1% at 70 to 79, and 1.2% at ages 80 years or older in men; the corresponding prevalence in women was 3.1%, 5.2%, 5.7%, 4.1%, 3.1%, 2.3%, and 1.2%, respectively. In both men and women, depression was correlated with infrequent bowel movement and daytime sleepiness, but the latter two were mutually independent. Conclusion: The presence of multiple nonmotor symptoms was uncommon in the general population and the prevalence was higher in women than in men. © 2014 International Parkinson and Movement Disorder Society.
Jukic A.M.,National Institute of Environmental Health and Safety |
Baird D.D.,National Institute of Environmental Health and Safety |
Weinberg C.R.,National Institute of Environmental Health and Safety |
Mcconnaughey D.R.,Westat Inc. |
Wilcox A.J.,National Institute of Environmental Health and Safety
Human Reproduction | Year: 2013
STUDY QUESTIONHow variable is the length of human pregnancy, and are early hormonal events related to gestational length?SUMMARY ANSWERAmong natural conceptions where the date of conception (ovulation) is known, the variation in pregnancy length spanned 37 days, even after excluding women with complications or preterm births.WHAT IS KNOWN ALREADYPrevious studies of length of gestation have either estimated gestational age by last menstrual period (LMP) or ultrasound (both imperfect measures) or included pregnancies conceived through assisted reproductive technology.STUDY DESIGN, SIZE, DURATIONThe Early Pregnancy Study was a prospective cohort study (1982-85) that followed 130 singleton pregnancies from unassisted conception to birth, with detailed hormonal measurements through the conception cycle; 125 of these pregnancies were included in this analysis.PARTICIPANTS/MATERIALS, SETTING, METHODSWe calculated the length of gestation beginning at conception (ovulation) in 125 naturally conceived, singleton live births. Ovulation, implantation and corpus luteum (CL) rescue pattern were identified with urinary hormone measurements. We accounted for events that artificially shorten the natural length of gestation (Cesarean delivery or labor induction, i.e. 'censoring') using Kaplan-Meier curves and proportional hazards models. We examined hormonal and other factors in relation to length of gestation. We did not have ultrasound information to compare with our gold standard measure.MAIN RESULTS AND THE ROLE OF CHANCEThe median time from ovulation to birth was 268 days (38 weeks, 2 days). Even after excluding six preterm births, the gestational length range was 37 days. The coefficient of variation was higher when measured by LMP (4.9%) than by ovulation (3.7%), reflecting the variability of time of ovulation. Conceptions that took longer to implant also took longer from implantation to delivery (P = 0.02). CL rescue pattern (reflecting ovarian response to implantation) was predictive (P = 0.006): pregnancies with a rapid progesterone rise were longer than those with delayed rise (a 12-day difference in the median gestational length). Mothers with longer gestations were older (P = 0.02), had longer pregnancies in other births (P < 0.0001) and were heavier at birth (P = 0.01). We did not see an association between the length of gestation and several factors that have been associated with gestational length in previous studies: body mass index, alcohol intake, parity or offspring sex.LIMITATIONS, REASONS FOR CAUTIONThe sample size was small and some exposures were rare, reducing power to detect weak associations.WIDER IMPLICATIONS OF THE FINDINGSHuman gestational length varies considerably even when measured exactly (from ovulation). An individual woman's deliveries tend to occur at similar gestational ages. Events in the first 2 weeks after conception are predictive of subsequent pregnancy length, and may suggest pathways underlying the timing of delivery. © The Author 2013.
McDonald L.,University of Toronto |
Thomas C.,Westat Inc.
International Psychogeriatrics | Year: 2013
Background: This paper provide. The findings from a large pilot study, Defining and Measuring Elder Abuse and Neglect, a precursor to a national prevalence study to be conducted in Canada beginning in September 2013. One purpose of this study an. The focus of this paper was to determine whether a life course perspective would provide a useful framework for examining elder abuse. The two-year pilot study, 2009-2011, examine. The prevalence of perceptions of abuse at each life stage by type of abuse. The importance of early life stage abuse in predicting types of elder abuse, and early life stage abuse as a risk factor for elder abuse. Methods: Older adults who were aged ≥55 years (N = 267) completed a cross-sectional telephone survey, comprising measures of five types of elder abuse (neglect, physical, sexual, psychological, and financial) and their occurrence acros. The life course: childhood (≤17 years), young adulthood (18 to 24 years), and older adulthood (5 to 12 months prior t. The interview date). Data analyses included descriptive statistics, bivariate correlations for abuse a. The various life stages, an. The estimation of logistic regression models that examined predictors of late life abuse, and multinomial logistic regression models predictin. The frequency of abuse. Results: Fifty-five percent o. The sample reported abuse during childhood, and 34.1% reported abuse during young adulthood. Forty-three percent said they were abused during mature adulthood, and 24.4% said they were abused since age 55 but prior t. The interview date o. The study. Psychological (42.3%), physical (26.6%), and sexual abuses (32.2%) wer. The most common abuses in childhood while psychological abuse wa. The most common type of abuse at each life stage. Whe. The risk factors for abuse were considered simultaneously including abuse during all three life stages, only a history of abuse during childhood retained its importance (OR = 1.81, p = 0.046, CI = 1.01-3.26). Abuse in childhood increase. The risk of experiencing one type of abuse relative to no abuse, but was also unrelated to experiencing two or more types of abuse compared to no abuse. Conclusions: Results suggest that a life course perspective provides a useful framework for understanding elder abuse and neglect. The findings indicate that a childhood history of abuse in this sample had a deciding influence on later mistreatment, over and above what happens later in life. © 2013 International Psychogeriatric Association.
Agency: NSF | Branch: Contract | Program: | Phase: RESEARCH & DEVELOPMENT STATIST | Award Amount: 3.19M | Year: 2011
Agency: NSF | Branch: Continuing grant | Program: | Phase: | Award Amount: 71.27K | Year: 2011
Every request to take part in a survey is framed in some way. This project consists of a set of experiments that investigate how the presentation of the survey request affects nonresponse and measurement error. The experiments are guided by a theory of survey participation (the salience-leverage theory) that claims that people decide whether to take part in a survey based on whatever aspects of the survey are made salient in the presentation of the survey request and on how they evaluate those features. Two initial experiments randomly vary the description of the topic and sponsor of the survey, with hypothesized effects both on nonresponse propensities and on reporting. In the third experiment, survey design features that can mediate or reduce the error-producing influences of the survey topic and sponsor will be examined. Thus, the project experimentally tests mechanisms producing nonresponse bias and measurement errors and, once these effects have been documented, provides guidance to the survey practitioner about how to reduce their impact.
While the research is theoretically motivated and features experimental control, there are important practical implications of the work for the federal statistical agencies and the larger survey community. Sometimes estimates of key social indicators (e.g., the prevalence of rape or the frequency of defensive use of handguns) vary widely across surveys. The effects explored in this project may help explain these discrepancies. In addition, this work will a) help agencies conducting surveys anticipate when different sponsors may obtain different results, b) provide evidence about potentially harmful effects on nonresponse error and measurement error of emphasizing a single purpose of a survey, and c) produce evidence regarding design features that can reduce the effects of the presentation of the survey on nonresponse and measurement error.
Lee S.,University of Michigan |
Brick J.M.,Westat Inc. |
Brown E.R.,University of California at Los Angeles |
Grant D.,University of California at Los Angeles
Health Services Research | Year: 2010
Objective. Examine the effect of including cell-phone numbers in a traditional landline random digit dial (RDD) telephone survey. Data Sources. The 2007 California Health Interview Survey (CHIS). Data Collection Methods. CHIS 2007 is an RDD telephone survey supplementing a landline sample in California with a sample of cell-only (CO) adults. Study Design. We examined the degree of bias due to exclusion of CO populations and compared a series of demographic and health-related characteristics by telephone usage. Principal Findings. When adjusted for noncoverage in the landline sample through weighting, the potential noncoverage bias due to excluding CO adults in landline telephone surveys is diminished. Both CO adults and adults who have both landline and cell phones but mostly use cell phones appear different from other telephone usage groups. Controlling for demographic differences did not attenuate the significant distinctiveness of cell-mostly adults. Conclusions. While careful weighting can mitigate noncoverage bias in landline telephone surveys, the rapid growth of cell-phone population and their distinctive characteristics suggest it is important to include a cell-phone sample. Moreover, the threat of noncoverage bias in telephone health survey estimates could mislead policy makers with possibly serious consequences for their ability to address important health policy issues. © Health Research and Educational Trust.
Agency: NSF | Branch: Standard Grant | Program: | Phase: PROGRAM EVALUATION | Award Amount: 1.14M | Year: 2013
This research study examines the extent and ways in which the first three Cohorts of MSP Partnership projects have sustained the accomplishments made during their respective grant periods. The study addresses two interrelated research questions: 1) What strategies did the initial cohorts of MSPs use to sustain and nurture their outcomes beyond their NSF award? and 2) What were the mediators that either facilitated or hindered projects efforts to sustain these outcomes? Guided by a logic model that lays out a proposed theory of sustainability, the study uses a mixed method approach to investigate factors influencing those changes at both school district and Institution of Higher Education (IHE) levels. The study is conducted in two phases: Phase 1 involves document review, discussions with current and former NSF project officers, and interviews with PIs and Co-PIs to provide a broad brush examination of project sustainability. Phase 2 includes case studies in a sample of projects to provide a fuller assessment of facilitators and hindrances. The specific approach for each case study will depend on the type of practice being sustained and the partners and participants involved in the practice.
Agency: NSF | Branch: Standard Grant | Program: | Phase: METHOD, MEASURE & STATS | Award Amount: 273.27K | Year: 2011
This research examines three forms of survey measurement error and investigates the relations among them. The first form of measurement error affects questions designed to identify members of the population eligible for a given survey (for example, persons over 65 years old). Several studies find that members of the eligible population are underreported in screening interviews. Although no survey perfectly covers its target population, surveys aimed at specific subpopulations seem especially prone to undercover that particular population. The second form of measurement error involves filter questions. These are questions that, depending on how they are answered, either lead to additional follow-up questions or to the respondents skipping out of the follow-up items. Many survey researchers believe that respondents are likely to give false answers to the filter questions in order to avoid the follow-up questions. As a result, many surveys ask the filter questions at the beginning of the questionnaire and administer the follow-up questions later on rather than interleaving the filter and follow-up questions. The final form of measurement error involves conditioning, or time-in-sample, effects. Over the last forty years, many survey researchers have suggested that respondents in ongoing panel surveys report fewer relevant events across waves of the panel survey and across time periods in a diary survey.
What the three phenomena appear to have in common is underreporting motivated by the desire to reduce the effort needed to complete the questionnaire. But it is not clear whether these forms of error result from something the interviewers do, something the respondents do, or both. The proposed studies use both new experiments and analyze existing data to try to pinpoint the locus of these effects (interviewers versus respondents) and to explore the effectiveness of different methods for reducing these errors. The project will contribute to the improvement of various national statistics that are derived from survey items affected by these problems. The project also will further the training of graduate students and contribute to the professional training of survey researchers at both institutions. The research is supported by the Methodology, Measurement, and Statistics Program and a consortium of federal statistical agencies as part of a joint activity to support research on survey and statistical methodology.
Agency: NSF | Branch: Standard Grant | Program: | Phase: | Award Amount: 63.18K | Year: 2014
Since the late 1970s, the National Science Foundation has sponsored a series of surveys to gauge public attitudes toward and understanding of science and technology. The scientific community has raised concerns about two of the survey items that have been part of the factual knowledge scale for many years. One of the items is intended to measure understanding of evolution, and the other is about the origins of the universe. In both items, there is a concern that a respondent?s answer may not be measuring scientific knowledge, but rather some aspect of religious belief. This potential interaction of religious belief and knowledge may vary among religious groups, and therefore influence the understanding of scientific knowledge in the U.S. population.
This proposal focuses on how different wordings of the questions about evolution and the origins of the universe may affect conclusions about science literacy. An experiment in the 2012 General Social Survey varied the question wording of these items by adding ?According to the theory of evolution?? or ?According to astronomers?? to stress that the questions are about the current state of scientific knowledge, not the respondent?s personal beliefs. Preliminary analyses show that higher percentages of the U.S. population answer these versions of the questions correctly than the original versions. This project investigates the measurement properties of these questions more thoroughly. We use confirmatory factor analysis to study measurement equivalence across religious groups on both the original and experimental versions of these science literacy measures.
The level of science literacy in the U.S. population can affect many aspects of society. Science literacy serves as a resource for individuals and communities. For example, individuals with higher levels of science literacy can make better decisions about their own health or the health of others. Science literacy can also impact economic growth and development by influencing factors such as the rate of new discoveries and technological development. Hence, it is important for policy makers to understand the level of science literacy in the population. The goal of this proposal is to clarify the degree to which survey questions provide accurate measures of science literacy. It specifically focuses on how different wordings of survey questions about the origins of the universe and evolution may affect how one draws conclusions about science literacy.
Agency: NSF | Branch: Standard Grant | Program: | Phase: | Award Amount: 601.92K | Year: 2013
This project will examine mobile devices, specifically smartphones and tablet computers, as vehicles for survey data collection. The appeal of these devices for survey researchers is clear. Because they are lightweight and relatively inexpensive, they make it easier to collect data using such existing survey modes as computer-assisted personal interviewing. The research will examine three issues raised by use of such devices. First, the input methods that these devices permit (such as touchscreen interfaces) are relatively unfamiliar to many users and may create response problems. Although these interfaces are sometimes used on laptops, tablets and smartphones require them, making usability concerns more central. Second, the screens on tablets and smartphones are considerably smaller than those on laptop or desktop computers. Experiments on web surveys demonstrate the importance of visual prominence. Any information that respondents need to use should be immediately visible to them without their having to perform any action (such as a mouse click) to make the information visible. Even the need for an eye movement may effectively render information invisible. Because of the small screens on mobile devices, it may be much harder to make all of the potentially useful information visible to respondents than it is with a laptop or desktop computer. The final issue is the perceived privacy of data collected on these devices. Respondents are willing to reveal sensitive information about themselves when a computer administers the questions, and web surveys seem to retain the advantages of earlier methods of computerized self-administration. But it is unclear whether respondents will display the same level of candor when the survey is administered over the Internet on a tablet computer or a smartphone. Two realistic field experiments and a usability study will examine these issues. Both experiments will be conducted in a single, face-to-face survey. The first experiment will compare laptop computers with tablets and smartphones and will examine the effects of both screen size and input method on breakoffs, missing data, completion times, and indicators of the quality of the responses. The second experiment will compare the same three data collection platforms as vehicles for collecting sensitive information. The experiment will ask respondents to assess the sensitivity of the questions, because item sensitivity may vary as a function of the device used to collect the data.
Surveys are a central tool for social scientists and policymakers in the United States, and survey research is a multi-billion dollar industry in the United States alone. Any set of technological advances, such as the widespread adoption of smartphones and tablet computers, is likely to have a major impact on how surveys are done. Although mobile devices will be widely used for surveys regardless of whether this research is done, the work will produce practical guidelines for using such devices to collect survey data and will alert survey researchers to some of the potential pitfalls of these devices.