Avoiding Randomization Failure in Program Evaluation, with Application to the Medicare Health Support Program

We highlight common problems in the application of random treatment assignment in large-scale program evaluation. Random assignment is the defining feature of modern experimental design, yet errors in design, implementation, and analysis often result in real-world applications not benefiting from its advantages. The errors discussed here cover the control of variability, levels of randomization, size of treatment arms, and power to detect causal effects, as well as the many problems that commonly lead to post-treatment bias. We illustrate these issues by identifying numerous serious errors in the Medicare Health Support evaluation and offering recommendations to improve the design and analysis of this and other large-scale randomized experiments.Governmen

Tilted String Cosmologies

Global symmetries of the string effective action are employed to generate tilted, homogeneous Bianchi type VI_h string cosmologies from a previously known stiff perfect fluid solution to Einstein gravity. The dilaton field is not constant on the surfaces of homogeneity. The future asymptotic state of the models is interpreted as a plane wave and is itself an exact solution to the string equations of motion to all orders in the inverse string tension. An inhomogeneous generalization of the Bianchi type III model is also found.Comment: 9 pages, Standard Latex Source. To appear in Physics Letters B Minor change: Authors now alphabetically liste

Response to Deborah Willis's “The Black Civil War Soldier: Conflict and Citizenship”

With references to my current research on African American World War II archives and from the poetry of Gwendolyn Brooks I use special forum to assert that Willis’s successful negotiation of the public and private realms of representation of black Civil War soldiers offers an excellent model for research on black soldiers in U.S. military conflicts and their quest for recognition and equal treatment as soldiers, citizens and people

Controlling Visible Light-Driven Photoconductivity in Self-Assembled Perylene Bisimide Structures

Alanine-functionalized perylene bisimides (PBI-A) are promising photoconductive materials. PBI-A self-assembles at high concentrations (mM) into highly ordered wormlike structures that are suitable for charge transport. However, we previously reported that the photoconductive properties of dried films of PBI-A did not correlate with the electronic absorption spectra as activity was only observed under UV light. Using transient absorption spectroscopy, we now demonstrate that charge separation can occur within these PBI-A structures in water under visible light. The lack of charge separation in the films is shown by DFT calculations to be due to a large ion-pair energy in the dried samples which is due to both the low dielectric environment and the change in the site of hole-localization upon drying. However, visible light photoconductivity can be induced in dried PBI-A films through the addition of methanol vapor, a suitable electron donor. The extension of PBI-A film activity into the visible region demonstrates that this class of self-assembled PBI-A structures may be of use in a heterojunction system when coupled to a suitable electron donor

Teaching African American Studies in the US and the UK

This is the first in what the Associate Editors hope will become a series of transatlantic exchanges about American Studies pedagogy. Conducted in the four months between January and April 2017, the discussion encompasses the political significance of African American Studies, the role of identity in the shaping of curricula and student responses to those curricula, and the challenges encountered by teachers at a variety of career stages and in a range of educational and geographic locations

TEF, Vol. 1 No. 1

https://scholarworks.sfasu.edu/tef/1000/thumbnail.jp