Value-Added Modeling for Teacher Effectiveness

[Excerpt] This report addresses issues associated with the evaluation of teacher effectiveness based on student growth in achievement. It focuses specifically on a method of evaluation referred to as value-added modeling (VAM). Although there are other methods for assessing teacher effectiveness, in the last decade, VAM has garnered increasing attention in education research and policy due to its promise as a more objective method of evaluation. The first section of this report describes what constitutes a VAM approach and how it estimates the so-called “teacher effect.” The second section identifies the components necessary to conduct VAM in education settings. Third, the report discusses current applications of VAM at the state and school district levels and what the research on these applications says about this method of evaluation. The fourth section of the report explains some of the implications these applications have for large-scale implementation of VAM. Finally, the report describes some of the federal policy options that might arise as Congress considers legislative action around these or related issues

The pressure moments for two rigid spheres in low-Reynolds-number flow

The pressure moment of a rigid particle is defined to be the trace of the first moment of the surface stress acting on the particle. A Faxén law for the pressure moment of one spherical particle in a general low-Reynolds-number flow is found in terms of the ambient pressure, and the pressure moments of two rigid spheres immersed in a linear ambient flow are calculated using multipole expansions and lubrication theory. The results are expressed in terms of resistance functions, following the practice established in other interaction studies. The osmotic pressure in a dilute colloidal suspension at small Péclet number is then calculated, to second order in particle volume fraction, using these resistance functions. In a second application of the pressure moment, the suspension or particle-phase pressure, used in two-phase flow modeling, is calculated using Stokesian dynamics and results for the suspension pressure for a sheared cubic lattice are reported

Industry views on water resources planning methods – prospects for change in England and Wales

This paper describes a qualitative study of practitioner perspectives on regulated water resources planning practice in England and Wales. The study focuses on strengths and weaknesses of existing practice and the case for change towards a risk-based approach informed by stochastic modelling assessments. In-depth, structured interviews were conducted to capture the views of planners, regulators and consultants closely involved in the planning process. We found broad agreement that the existing water availability assessment methods are fallible; they lack transparency, are often highly subjective and may fail to adequately expose problems of resilience. While most practitioners believe these issues warrant a more detailed examination of risk in the planning process, few believe there is a strong case for a fundamental shift towards risk-based planning informed by stochastic modelling assessments. The study identifies perceived business risks associated with change and exposes widespread scepticism of stochastic methods

Comparing the Performance of Alternative Exchange Arrangements

The volatility of the world economy since the breakdown of the Bretton Woods par value system of exchange rates has led many policymakers and economists to call for reform of the international monetary system. Many critics of the current "non-system" call for tighter international rules of the game in macroeconomic policy making. The proposed systems cover a wide spectrum of measures including maintaining the current flexible exchange rate system but with increased consultations between the major economies; a "target zone " system as advocated by John Williamson; or a full return to a system of fixed exchange rates as advocated by Ronald McKinnon This paper presents and applies a methodology useful for studying the operating characteristics of a number of alternative monetary arrangements using a large-scale simulation model of the world economy. We consider the performance of the regimes when policymakers do or do not observe the shocks, and when policymakers infer the shocks using an optimal filtering rule. Although the results are model specific and at best illustrative of the issues involved, the approach does have the advantage of providing a richer framework of analysis than is possible in simple models of international interdependence.