Experimenter Presence or Absence: An Experimental Analogue with Implications for Organizational Behavior Management

Students performed a simulated bank-proofing task individually in a lab with either the experimenter present or absent. Although run rates were similar, those in the Experimenter-Absent Group were off-task twice as much during sessions. Error frequencies for both groups were low and similar while rates of responding were significantly higher (+13%) in the Experimenter-Present Group because participants were off-task less often. Most human lab experiments fail to specify whether experimenters are present or absent in the room and this extraneous variable is a potential confound that should be controlled in future studies.     

Is “Sexual Competence” at First Heterosexual Intercourse Associated With Subsequent Sexual Health Status?

The timing of first sexual intercourse is often defined in terms of chronological age, with particular focus on “early” first sex. Arguments can be made for a more nuanced concept of readiness and appropriateness of timing of first intercourse. Using data from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3), conducted in 2010–2012, this study examined whether a context-based measure of first intercourse—termed sexual competence—was associated with subsequent sexual health in a population-based sample of 17-to 24-year-olds residing in Britain (n = 2,784). Participants were classified as “sexually competent” at first intercourse if they reported the following four criteria: contraceptive protection, autonomy of decision (not due to external influences), that both partners were “equally willing,” and that it happened at the “right time.” A lack of sexual competence at first intercourse was independently associated with testing positive for human papillomavirus (HPV) at interview; low sexual function in the past year; and among women only, reported sexually transmitted infection (STI) diagnosis ever; unplanned pregnancy in the past year; and having ever experienced nonvolitional sex. These findings provide empirical support for defining the nature of first intercourse with reference to contextual aspects of the experience, as opposed to a sole focus on chronological age at occurrence.     

Nonparametric Two‐Sample Tests of the Marginal Mark Distribution with Censored Marks

Occasionally, investigators collect auxiliary marks at the time of failure in a clinical study. Because the failure event may be censored at the end of the follow‐up period, these marked endpoints are subject to induced censoring. We propose two new families of two‐sample tests for the null hypothesis of no difference in mark‐scale distribution that allows for arbitrary associations between mark and time. One family of proposed tests is a nonparametric extension of an existing semi‐parametric linear test of the same null hypothesis while a second family of tests is based on novel marked rank processes. Simulation studies indicate that the proposed tests have the desired size and possess adequate statistical power to reject the null hypothesis under a simple change of location in the marginal mark distribution. When the marginal mark distribution has heavy tails, the proposed rank‐based tests can be nearly twice as powerful as linear tests.     

Modelling population-based cancer survival trends using join point models for grouped survival data

Summary.  In the USA cancer as a whole is the second leading cause of death and a major burden to health care; thus medical progress against cancer is a major public health goal. There are many individual studies to suggest that cancer treatment breakthroughs and early diagnosis have significantly improved the prognosis of cancer patients. To understand better the relationship between medical improvements and the survival experience for the patient population at large, it is useful to evaluate cancer survival trends on the population level, e.g. to find out when and how much the cancer survival rates changed. We analyse population-based grouped cancer survival data by incorporating join points into the survival models. A join point survival model facilitates the identification of trends with significant change-points in cancer survival, when related to cancer treatments or interventions. The Bayesian information criterion is used to select the number of join points. The performance of the join point survival models is evaluated with respect to cancer prognosis, join point locations, annual percentage changes in death rates by year of diagnosis and sample sizes through intensive simulation studies. The model is then applied to grouped relative survival data for several major cancer sites from the 'Surveillance, epidemiology and end results' programme of the National Cancer Institute. The change-points in the survival trends for several major cancer sites are identified and the potential driving forces behind such change-points are discussed.     

An exploration of attitudes toward female genital cutting in Nigeria

Female genital cutting (FGC) continues to be widespread particularly in sub-Saharan African countries. We use data from the 1999 Nigeria Demographic and Health Survey to consider factors that influence attitudes toward this procedure held by Nigerian women aged 15–49. We test four models: model 1 explores whether attitudes are consistent with a view of FGC as a social convention associated with marriageability of women. Model 2 examines the impact of modernization factors such as education and urbanization. In model 3, the influence of media and community activities are considered. Model 4 includes all of the factors in the three previous models. We find strong support for considering FGC a social convention. Modernization has minimal impact on attitudes about FGC mainly through its influence on the social convention.

Partitioning the effects of habitat fragmentation on rodent species richness in an urban landscape

Habitat fragmentation plays a major role in species extinction around the globe. Previous research has determined that species richness in fragments is affected by a number of characteristics. These include fragment age, size, and isolation, edge effects, vegetation coverage, habitat heterogeneity, and matrix content. Although most studies focused on one or a few of these characteristics, multiple characteristics work together to affect species richness, showing that the effects of habitat fragmentation are complex. The goal of our study was to partition the complex effects of habitat fragmentation by determining the direct, indirect, and cumulative effects of multiple habitat fragment characteristics on rodent species richness. In 2013, we determined rodent species richness in 25 habitat fragments within Thousand Oaks, California. In addition, we measured the following characteristics for each fragment: fragment age, area, isolation, shrub coverage, habitat heterogeneity, perimeter/area ratio, and percent non-urban buffer. Path Analysis was used to test the hypothesized model which described the direct, indirect, and cumulative effect of each habitat fragment characteristic on rodent species richness. Overall, the path model explained 67 % of the variation in rodent species richness among habitat fragments. Habitat heterogeneity had the greatest direct and total effect on rodent species richness. Fragment size had the next greatest total effect on rodent species richness but this was nearly entirely indirect through its influence on habitat heterogeneity, suggesting that large fragments containing the greatest diversity of habitats will support the most species. Our study shows that large habitat fragments support the greatest habitat diversity, which provides the highest likelihood of conserving rodent species richness in an urban landscape.     

Open media or echo chamber: the use of links in audience discussions on the Facebook Pages of partisan news organizations

This study evaluates the use of hyperlinks in audience discussions on the Facebook Pages of two partisan cable news organizations: the liberal-leaning Rachel Maddow Show and the conservative O'Reilly Factor, to investigate to what extent linking might intensify partisan political discussion or infuse a variety of perspectives into online communication. The results suggest that these Facebook audiences show a preference for a small group of information resources; furthermore, the two audiences shared an even smaller number of information resources in common. The findings support previous research that suggests a relatively small number of information resources receive most of the news audience traffic, and provide some support for other studies that indicate that partisan political discussions on social media are segregated by political orientation.     

The life of the Tea Party: Differences between Tea Party and Republican media use and political variables

The Tea Party has been identified by most mass media sources as a separate but related element of the Republican Party. This study adds to a new body of literature on the Tea Party by using polarization literature and survey data to (a) separate Tea Party Republicans (TPR), Tea Party Non-Republicans (TPNR), and Non–Tea Party Republicans; (b) identify the role of Tea Party affiliation (or lack thereof) on political interest and media use; and (c) assess the role of media use by these three groups on political interest and voting. This study found that partisan media plays an important role for all three groups and it especially has the strongest role for those who do not align themselves with the Republican Party. Specifically, both TPR and TPNR were more likely to be politically interested and rely on partisan media than Republicans who are not affiliated with the Tea Party.