2,315 research outputs found

    To Aggregate, Pool, or Neither: Testing the Rational Expectations Hypothesis Using Survey Data

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    It is well known that even if all forecasters are rational, estimated coefficients in unbiasedness regressions using consensus forecasts are inconsistent because forecasters have private information. However, if all forecasters face a common realization, pooled estimators are also inconsistent. In contrast, we show that when predictions and realizations are integrated and cointegrated, micro-homogeneity ensures that consensus and pooled estimators are consistent. Therefore, contrary to claims in the literature, in the absence of micro-homogeneity, pooling is not a solution to the aggregation problem. We reject micro-homogeneity for a number of forecasts from the Survey of Professional Forecasters. Therefore, for these variables unbiasedness can only be tested at the individual level.Rational Expectations, Micro-homogeneity, Heterogeneity Bias, Aggregation Bias, Survey Forecasts

    Testing the Rational Expectations Hypothesis using Survey Data

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    Because of the importance of inflation expectations, Lloyd B. Thomas Jr. (Fall 1999, p. 125-44) reexamines "the evidence on the nature and performance of various measures of expected inflation, with special attention given to the issue of rationality" (p. 126). Thomas tests the unbiasedness hypothesis using the Livingston and Michigan survey forecasts for the 1960 to 1997 time period and is unable to reject the null hypothesis of unbiasedness. Unfortunately, two types of problems due to aggregation plague such tests: private information bias and micro-heterogeneity bias. Therefore, for these survey forecasts, consensus regressions should generally not be used to test rationality; rationality can only be tested at the individual level.

    Sharing Jesus with Muslims: A Survey of Church Leaders in Africa

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    A web survey of 34 pastors and other church leaders in 2020 who had met during graduate studies at Africa International University (AIU) was conducted to understand what is being done in Muslim evangelism in their home churches, primarily in East Africa. They generally characterized Muslims positively, as being made in the image of God, and as needing salvation through Jesus. They identified what they considered to be key differences between Muslims and Christians. Half of their churches made general evangelistic efforts, but most of these made no specific attempt to share the gospel with Muslims. Sharing the gospel with Muslims presents different challenges than sharing the gospel with people of other faiths. Their church members need a deeper understanding of the basic doctrines of the Trinity and salvation through Christ, along with training and tools on how to present the gospel to Muslims in a way they can hear, understand, and accept

    Safety in Numbers: A strategy for cycling?

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    Jennifer Bonham, Stuart Cathcart, John Petkov and Peter Lum

    The Molson Coors Operational Portfolio Architecture: A Case Study

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    After decades of progress, IT projects are still too likely to fail. Managing projects for success has become a critical goal for many organizations. Project portfolio management started in the Coors Brewing Company (CBC) as a way to improve the success rates of IT projects. Before the creation of an IT program management office (PMO) about 65 percent of running projects were rated as healthy (essentially on-time and on-budget); after the creation of the IT PMO, as many as 95 percent of the ongoing projects became rated as healthy. While the IT PMO was dramatically improving the efficiency of the IT organization, the New Product Packages (NPP) organization was implementing its own product program management office. Ultimately, the combined buzz of these two success stories within Coors led the CEO to sanction the creation of a U.S.-divisional PMO - known as the CBC PMO. With the recent merger with Molson Canada another layer was created called the Global PMO. What started as a strategic IT initiative ended up changing the entire culture and framework of the company - Coors had entered the elite group of companies that could prove stellar technology investment success rates. Now, while its vision is to create PMOs in its other two subsidiaries, Coors Brewers Limited (CBL) and Molson Canada, as it did with the creation of its CBC PMO, the company is running into some new challenges. This case study is split into four main sections: Introduction, Background (Coors history, project portfolio management history), IT PMO, and Global PMO. In the introduction we present the two organizations that have driven the creation of the Molson-Coors operational portfolio architecture: the IT PMO and the Global PMO. This summary then allows us to frame the four core problems of this paper in both the context of these two PMOs and in the context of the recent merger with Molson, Inc. After clarifying the goals of the paper, we then step back and review the history of the Coors Brewing Company and the history of project portfolio management. With the goals outlined and the background established, we start the section on the evolution of the IT PMO. Finally, in the last section, we show how the four core problems derived from the Global PMO and how lessons learned from the IT PMO may be applied. We hope that by framing the four problems from different perspectives (corporate history, industry approaches, IT PMO evolution and the Global PMO architecture) the reader will be able to more easily develop solutions

    Hepatic resection for metastatic colorectal adenocarcinoma: A proposal of a prognostic scoring system

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    Background: Hepatic resection for metastatic colorectal cancer provides excellent longterm results in a substantial proportion of patients. Although various prognostic risk factors have been identified, there has been no dependable staging or prognostic scoring system for metastatic hepatic tumors. Study Design: Various clinical and pathologic risk factors were examined in 305 consecutive patients who underwent primary hepatic resections for metastatic colorectal cancer. Survival rates were estimated by the Cox proportional hazards model using the equation: S(t) = [S(o)(t)](exp(R - R(o))), where S(o)(t) is the survival rate of patients with none of the identified risk factors and R(o) = 0. Results: Preliminary multivariate analysis revealed that independently significant negative prognosticators were: (1) positive surgical margins, (2) extrahepatic tumor involvement including the lymph node(s), (3) tumor number of three or more, (4) bilobar tumors, and (5) time from treatment of the primary tumor to hepatic recurrence of 30 months or less. Because the survival rates of the 62 patients with positive margins or extrahepatic tumor were uniformly very poor, multivariate analysis was repeated in the remaining 243 patients who did not have these lethal risk factors. The reanalysis revealed that independently significant poor prognosticators were: (1) tumor number of three or more, (2) tumor size greater than 8 cm, (3) time to hepatic recurrence of 30 months or less, and (4) bilobar tumors. Risk scores (R) for tumor recurrence of the culled cohort (n = 243) were calculated by summation of coefficients from the multivariate analysis and were divided into five groups: grade 1, no risk factors (R = 0); grade 2, one risk factor (R = 0.3 to 0.7); grade 3, two risk factors (R = 0.7 to 1.1); grade 4, three risk factors (R = 1.2 to 1.6); and grade 5, four risk factors (R > 1.6). Grade 6 consisted of the 62 culled patients with positive margins or extrahepatic tumor. Kaplan-Meier and Cox proportional hazards estimated 5-year survival rates of grade 1 to 6 patients were 48.3% and 48.3%, 36.6% and 33.7%, 19.9% and 17.9%, 11.9% and 6.4%, 0% and 1.1%, and 0% and 0%, respectively (p < 0.0001). Conclusions: The proposed risk-score grading predicted the survival differences extremely well. Estimated survival as determined by the Cox proportional hazards model was similar to that determined by the Kaplan-Meier method. Verification and further improvements of the proposed system are awaited by other centers or international collaborative studies

    Women are underrepresented in computational biology:An analysis of the scholarly literature in biology, computer science and computational biology

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    While women are generally underrepresented in STEM fields, there are noticeable differences between fields. For instance, the gender ratio in biology is more balanced than in computer science. We were interested in how this difference is reflected in the interdisciplinary field of computational/quantitative biology. To this end, we examined the proportion of female authors in publications from the PubMed and arXiv databases. There are fewer female authors on research papers in computational biology, as compared to biology in general. This is true across authorship position, year, and journal impact factor. A comparison with arXiv shows that quantitative biology papers have a higher ratio of female authors than computer science papers, placing computational biology in between its two parent fields in terms of gender representation. Both in biology and in computational biology, a female last author increases the probability of other authors on the paper being female, pointing to a potential role of female PIs in influencing the gender balance
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