Using the contribution matrix to evaluate complex study limitations in a network meta-analysis: a case study of bipolar maintenance pharmacotherapy review.

BACKGROUND Limitations in the primary studies constitute one important factor to be considered in the grading of recommendations assessment, development, and evaluation (GRADE) system of rating quality of evidence. However, in the network meta-analysis (NMA), such evaluation poses a special challenge because each network estimate receives different amounts of contributions from various studies via direct as well as indirect routes and because some biases have directions whose repercussion in the network can be complicated. FINDINGS In this report we use the NMA of maintenance pharmacotherapy of bipolar disorder (17 interventions, 33 studies) and demonstrate how to quantitatively evaluate the impact of study limitations using netweight, a STATA command for NMA. For each network estimate, the percentage of contributions from direct comparisons at high, moderate or low risk of bias were quantified, respectively. This method has proven flexible enough to accommodate complex biases with direction, such as the one due to the enrichment design seen in some trials of bipolar maintenance pharmacotherapy. CONCLUSIONS Using netweight, therefore, we can evaluate in a transparent and quantitative manner how study limitations of individual studies in the NMA impact on the quality of evidence of each network estimate, even when such limitations have clear directions.

Potential Impact of Sexual Transmission on Ebola Virus Epidemiology: Sierra Leone as a Case Study.

BACKGROUND Sexual transmission of Ebola virus disease (EVD) 6 months after onset of symptoms has been recently documented, and Ebola virus RNA has been detected in semen of survivors up to 9 months after onset of symptoms. As countries affected by the 2013-2015 epidemic in West Africa, by far the largest to date, are declared free of Ebola virus disease (EVD), it remains unclear what threat is posed by rare sexual transmission events that could arise from survivors. METHODOLOGY/PRINCIPAL FINDINGS We devised a compartmental mathematical model that includes sexual transmission from convalescent survivors: a SEICR (susceptible-exposed-infectious-convalescent-recovered) transmission model. We fitted the model to weekly incidence of EVD cases from the 2014-2015 epidemic in Sierra Leone. Sensitivity analyses and Monte Carlo simulations showed that a 0.1% per sex act transmission probability and a 3-month convalescent period (the two key unknown parameters of sexual transmission) create very few additional cases, but would extend the epidemic by 83 days [95% CI: 68-98 days] (p < 0.0001) on average. Strikingly, a 6-month convalescent period extended the average epidemic by 540 days (95% CI: 508-572 days), doubling the current length, despite an insignificant rise in the number of new cases generated. CONCLUSIONS/SIGNIFICANCE Our results show that reductions in the per sex act transmission probability via abstinence and condom use should reduce the number of sporadic sexual transmission events, but will not significantly reduce the epidemic size and may only minimally shorten the length of time the public health community must maintain response preparedness. While the number of infectious survivors is expected to greatly decline over the coming months, our results show that transmission events may still be expected for quite some time as each event results in a new potential cluster of non-sexual transmission. Precise measurement of the convalescent period is thus important for planning ongoing surveillance efforts.

Lessons from Ellen: A Case Study Investigation of Comprehension Strategy Instruction in Action

In the past ten years, reading comprehension instruction has received significant attention from educational researchers. Drawing on studies from cognitive psychology, reader response theory, and language arts research, current best practice in reading comprehension instruction is characterized by a strategies approach in which students are taught to think like proficient readers who visualize, infer, activate schema, question, and summarize as they read. Studies investigating the impact of comprehension strategy instruction on student achievement in reading suggest that when implemented consistently the intervention has a positive effect on achievement. Research also shows, however, that few teachers embrace this approach to reading instruction despite its effectiveness, even when the conditions for substantive professional development (i.e. prolonged engagement, support, resources, time) are present. The interpretive case study reported in this dissertation examined the year-long experience of one fourth grade teacher, Ellen, as she leanled about comprehension strategy instruction and attempted to integrate the approach in her reading program. The goal of the study was to extend current understanding of the factors that support or inhibit an individual teacher's instructional decision making. The research explored how Ellen's academic preparation, beliefs about reading comprehension instruction, and attitudes toward teacher-student interaction influenced her efforts to employ comprehension strategy instruction. Qualitative methods were the basis of this study's research design. The primary methods for collecting data included pre- and post-interviews, field notes from classroom observations and staff development sessions, infonnal interviews, e-mail correspondence, and artifacts such as reading assignments, professional writing, school newsletters, and photographs of the classroom. Transcripts from interviews, as well as field notes, e-mail, and artifacts, were analyzed according to grounded theory's constant-comparative method. The results of the study suggest that three factors were pivotal in Ellen's successful implementation of reading strategy instruction: Pedagogical beliefs, classroom relationships, and professional community. Research on instructional change generally focuses on issues of time, resources, feedback, and follow-through. The research reported here recognizes the importance of these components, but expands contemporary thinking by showing how, in Ellen's case, a teacher's existing theories, her relationship with her students, and her professional interaction with peers impact instructional decisions.

The Black-White Achievement Gap Amongst Struggling Readers: A Case Study of Early Intervention Outcomes in Massachusetts

A number of analyses of large data sets have suggested that the reading achievement gap between African American and White U.S. is negligible or small at school entry, but widens substantially during the school years because African American students show slower rates of growth in elementary and secondary school. Identifying when and why gaps occur, therefore, is a an important research endeavor. In addition, being able to predict which African American children are most likely to fall behind can contribute to efforts to close the achievement gap. This paper analyzes first grade and third grade data on African American and White children in Massachusetts who all were identified in first grade as struggling readers and enrolled in Reading Recovery—an individualized intervention. All the children were low-income and attending urban schools. Using Observation Survey data from first grade, and MCAS Reading data from 3rd grade, we found that the African American and White students made equal average progress while in first grade, but by the end of third grade showed a large gap in MCAS proficiency rates. We discuss the results in terms of school quality, reading development, dialect issues, testing formats, and the need to provide long-term support to vulnerable learners.