A Reanalysis of the Effects of Teacher Replacement Using Value-Added Modeling

2013 ◽  
Vol 115 (12) ◽  
pp. 1-35
Author(s):  
Stuart S. Yeh
Keyword(s):  
Student Achievement ◽  
Large Scale ◽  
Reliability And Validity ◽  
Value Added ◽  
Cost Effective ◽  
Large Numbers ◽  
Cost Effective Approach ◽  
Need To Evaluate ◽  
Value Added Modeling ◽  
Lifetime Earnings

Background In principle, value-added modeling (VAM) might be justified if it can be shown to be a more reliable indicator of teacher quality than existing indicators for existing low-stakes decisions that are already being made, such as the award of small merit bonuses. However, a growing number of researchers now advocate the use of VAM to identify and replace large numbers of low-performing teachers. There is a need to evaluate these proposals because the active termination of large numbers of teachers based on VAM requires a much higher standard of reliability and validity. Furthermore, these proposals must be evaluated to determine if they are cost-effective compared to alternative proposals for raising student achievement. While VAM might be justified as a replacement for existing indicators (for existing decisions regarding merit compensation), it might not meet the higher standard of reliability and validity required for large-scale teacher termination, and it may not be the most cost-effective approach for raising student achievement. If society devotes its resources to approaches that are not cost-effective, the increase in achievement per dollar of resources expended will remain low, inhibiting reduction of the achievement gap. Objective This article reviews literature regarding the reliability and validity of VAM, then focuses on an evaluation of a proposal by Chetty, Friedman, and Rockoff to use VAM to identify and replace the lowest-performing 5% of teachers with average teachers. Chetty et al. estimate that implementation of this proposal would increase the achievement and lifetime earnings of students. The results appear likely to accelerate the adoption of VAM by school districts nationwide. The objective of the current article is to evaluate the Chetty et al. proposal and the strategy of raising student achievement by using VAM to identify and replace low-performing teachers. Method This article analyzes the assumptions of the Chetty et al. study and the assumptions of similar VAM-based proposals to raise student achievement. This analysis establishes a basis for evaluating the Chetty et al. proposal and, in general, a basis for evaluating all VAM-based policies to raise achievement. Conclusion VAM is not reliable or valid, and VAM-based polices are not cost-effective for the purpose of raising student achievement and increasing earnings by terminating large numbers of low-performing teachers.

scholarly journals Multi-Country Scale Assessment of Available Energy Recovery Potential Using Micro-Hydropower in Drinking, Pressurised Irrigation and Wastewater Networks, Covering Part of the EU

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 899
Author(s):  
Djordje Mitrovic ◽  
Miguel Crespo Chacón ◽  
Aida Mérida García ◽  
Jorge García Morillo ◽  
Juan Antonio Rodríguez Diaz ◽  
...  
Keyword(s):  
Drinking Water ◽  
Northern Ireland ◽  
Energy Recovery ◽  
Large Scale ◽  
Significant Proportion ◽  
Value Added ◽  
Cost Effective ◽  
Net Energy ◽  
Water Networks ◽  
Scale Assessment

Studies have shown micro-hydropower (MHP) opportunities for energy recovery and CO2 reductions in the water sector. This paper conducts a large-scale assessment of this potential using a dataset amassed across six EU countries (Ireland, Northern Ireland, Scotland, Wales, Spain, and Portugal) for the drinking water, irrigation, and wastewater sectors. Extrapolating the collected data, the total annual MHP potential was estimated between 482.3 and 821.6 GWh, depending on the assumptions, divided among Ireland (15.5–32.2 GWh), Scotland (17.8–139.7 GWh), Northern Ireland (5.9–8.2 GWh), Wales (10.2–8.1 GWh), Spain (375.3–539.9 GWh), and Portugal (57.6–93.5 GWh) and distributed across the drinking water (43–67%), irrigation (51–30%), and wastewater (6–3%) sectors. The findings demonstrated reductions in energy consumption in water networks between 1.7 and 13.0%. Forty-five percent of the energy estimated from the analysed sites was associated with just 3% of their number, having a power output capacity >15 kW. This demonstrated that a significant proportion of energy could be exploited at a small number of sites, with a valuable contribution to net energy efficiency gains and CO2 emission reductions. This also demonstrates cost-effective, value-added, multi-country benefits to policy makers, establishing the case to incentivise MHP in water networks to help achieve the desired CO2 emissions reductions targets.

scholarly journals The High Capacity Expanding Lifeboat HiCEL – Meeting the Modern SAR Challenge

2018 ◽  
Author(s):  
J R E Wright ◽  
G E Payne
Keyword(s):  
Large Scale ◽  
High Capacity ◽  
Cost Effective ◽  
Second World War ◽  
Concept Design ◽  
Small Vessels ◽  
Large Numbers ◽  
Cost Effective Alternative ◽  
Operational Envelope ◽  
Second World

The Mediterranean migrant crisis has resulted in the highest population displacement since the Second World War. In 2016 alone, over one million made the journey across the sea. Since 2013 over 15,000 have died as a result of this journey. Small vessels such as wooden fishing boats and RIBs are commonly used by smugglers as transport. These are often unseaworthy and filled with numbers of passengers far exceeding their intended capacity. When failure occurs, rescues are typically conducted by the nearest available vessel. These vessels are often ill-equipped for a large-scale Search and Rescue (SAR) operation making it highly dangerous for all involved.  The size and quantity of lifeboats available are often insufficient for the large numbers of people to be rescued; as a result, repeat journeys are required, making the rescue process slow, inefficient and hazardous. This paper outlines a novel solution to this problem. A concept design is presented for a rapidly expandable lifeboat capable of holding large numbers of passengers, whilst still fitting into the operational envelope of common davits. The unique inflatable design can be deployed quickly from a range of vessels and aeroplanes offering an immediate platform from which disembarkation onto a suitable vessel can be achieved. CONOPS are outlined along with the required capabilities of the design. Drop stitch technology is identified as a viable means of manufacturing the large inflatable platforms. Finally, the paper discusses an alternative solution, retrofitting existing enclosed lifeboats with the solution to offer a more cost-effective alternative.  

A cost effective approach to stormwater management? source control and distributed storage

1997 ◽  
Vol 36 (8-9) ◽  
pp. 307-311 ◽  
Author(s):  
R. Y. G. Andoh ◽  
C. Declerck
Keyword(s):  
Large Scale ◽  
Traditional Approach ◽  
Distributed Storage ◽  
Cost Effective ◽  
Source Control ◽  
Slowing Down ◽  
Surface Areas ◽  
Cost Effective Approach ◽  
Receiving Waters ◽  
The Cost

Rapid urbanisation and its consequent increase in impermeable surface areas and changes in land use has generally resulted in problems of flooding and heavy pollution of urban streams and other receiving waters. This has often been coupled with ground water depletion and a threat to water resources. The first part of this paper presents an alternative drainage philosophy and strategy which mimics nature's way by slowing down (attenuating) the movement of urban runoff. This approach results in cost-effective, affordable and sustainable drainage schemes. The alternative strategy can be described as one of prevention rather than cure by effecting controls closer to source rather than the traditional approach which results in the transfer of problems downstream, resulting in its cumulation and the need for large scale, centralised control. The second part describes a research project which has been launched in order to quantify the cost and operational benefits of source control and distributed storage. Details of the methodology of the modelling and simulation processes which are being followed to achieve this target are presented.

Electro-reduction of hematite using water as the redox mediator

2019 ◽  
Vol 21 (2) ◽  
pp. 198-204 ◽  
Author(s):  
Kaiyu Xie ◽  
Ali Reza Kamali
Keyword(s):  
Molten Salt ◽  
Large Scale ◽  
Cost Effective ◽  
Redox Mediator ◽  
Electrolytic Reduction ◽  
Scale Production ◽  
Large Scale Production ◽  
Cost Effective Approach

Molten salt electrolytic reduction of Fe2O3 in the presence of water is proposed as a sustainable and cost-effective approach for large-scale production of iron.

scholarly journals A Green and Cost-effective Approach to Reutilize the Effluent from Bleaching Process

2019 ◽  
pp. 85-90
Keyword(s):  
Large Scale ◽  
Environmental Science ◽  
Cost Effective ◽  
Synthetic Dyes ◽  
High Concentration ◽  
Cost Effective Approach ◽  
Color Yield ◽  
Wet Processing ◽  
Dyed Fabric ◽  
Textile Sector

Environmental science and management is often the most discussed subject nowadays all over the world. In a number of countries, presently plenty of harms are associated with the effluent by industrial due to growing industrialization; this issue should be considered at large scale. Textile sector is one of the leading areas, which uses a high amount of chemicals and creating environmental pollution. Textile wet processing sector uses a lot of chemicals, surfactants and synthetic dyes, hence produce a large amount of wastewater having a high concentration of chemicals. This research is an effort to investigate the amount of residue remained in liquor after bleaching and reuses this liquor by adding a few chemicals according to the requirement. Afterward, the comparison was made between the bleached sample with fresh liquor and bleached sample with reused liquor. It was observed that bleaching with reused liquor shows good results though these results are insignificantly less than fresh bleaching liquor. On the other hand, fortunately, the color yield of dyed fabric bleached with reused liquor is higher than fresh liquor.

scholarly journals Biotechnological Valorization of Pectinolytics and Their Industrial Applications: A Review

2014 ◽  
Vol 9 (11) ◽  
pp. 1934578X1400901 ◽  
Author(s):  
Muhammad Irshad ◽  
Muhammad Asgher ◽  
Zahid Anwar ◽  
Aftab Ahmad
Keyword(s):  
Large Scale ◽  
Value Added ◽  
Cost Effective ◽  
Industrial Applications ◽  
Green Biotechnology ◽  
A Value ◽  
Physico Chemical ◽  
Target Yield ◽  
High Yields ◽  
Agricultural Materials

In the last several years, in serious consideration of the worldwide economic and environmental issues there has been an increasing research interest in the value of naturally occurring bio-sourced materials. Agro-industrial based biomass comprised of pectin is an inexpensive, renewable, abundant natural resource that could be utilized for large-scale and cost-effective production of natural products i.e., pectinolytics. Pectinolytics are one of the most widely distributed enzymes in bacteria, fungi and plants. From ancient times to date, many methods have been introduced to improve the optimization of pectinolytics to obtain high yields of maximal purity. To expand the range of natural bio-resources the rapidly evolving tools of biotechnology can lower the conversion costs and also enhance target yield of the product of interest. This green biotechnology presents a promising approach to convert most of the agricultural materials into a value-added product with multiple applications. Major advances have already been achieved in recent years in order to obtain high levels of purity with optimal yields. The present review begins with an overview of pectinolytics and their physico-chemical features, and their specific role with classification based on pectic materials. Information is also given on the culture influences and potential sources of pectinolytics, followed by a brief summary of various industrial and biotechnological applications and future considerations.

Integration of NuScale SMR With Desalination Technologies

2014 ◽  
Author(s):  
D. T. Ingersoll ◽  
Z. J. Houghton ◽  
R. Bromm ◽  
C. Desportes
Keyword(s):  
Large Scale ◽  
Nuclear Reactor ◽  
Cost Effective ◽  
Water Desalination ◽  
Plant Design ◽  
Electrical Grids ◽  
Cost Effective Approach ◽  
Attractive Option ◽  
Parametric Studies ◽  
New Generation

Nuclear energy plants are attractive energy source for large scale water desalination since the thermal energy produced in a nuclear reactor can provide both electricity and steam to desalt water without the production of greenhouse gases. A particularly attractive option is to couple a desalination plant with the new generation of nuclear plant designs: small modular reactors (SMR). This allows regions with smaller electrical grids and limited infrastructure to add new electrical and water capacity in more appropriate increments and allows countries to consider siting plants at a broader range of distributed locations. The NuScale SMR plant design is especially well suited for the co-generation of electricity and desalted water. The enhanced safety, improved affordability, and deployment flexibilities of the NuScale design provide a cost-effective approach to expanding global desalination capacity. Parametric studies have been performed to evaluate technical options for coupling a NuScale plant to a variety of different desalination technologies. An economic comparison of these options was performed for each of the different desalination technologies coupled to an appropriately sized NuScale plant capable of providing sufficient carbon-free electricity and clean water to support a city of 300,000 people.

Volunteer Science

2016 ◽  
Vol 79 (4) ◽  
pp. 376-396 ◽  
Author(s):  
Jason Radford ◽  
Andy Pilny ◽  
Ashley Reichelmann ◽  
Brian Keegan ◽  
Brooke Foucault Welles ◽  
...  
Keyword(s):  
Large Scale ◽  
Effective Means ◽  
Cost Effective ◽  
Social Psychological ◽  
Timely Manner ◽  
Online Laboratory ◽  
Large Numbers ◽  
Large Scale Survey ◽  
Online Methods ◽  
Psychological Experiments

Experimental research in traditional laboratories comes at a significant logistic and financial cost while drawing data from demographically narrow populations. The growth of online methods of research has resulted in effective means for social psychologists to collect large-scale survey-based data in a cost-effective and timely manner. However, the same advancement has not occurred for social psychologists who rely on experimentation as their primary method of data collection. The aim of this article is to provide an overview of one online laboratory for conducting experiments, Volunteer Science, and report the results of six studies that test canonical behaviors commonly captured in social psychological experiments. Our results show that the online laboratory is capable of performing a variety of studies with large numbers of diverse volunteers. We advocate for the use of the online laboratory as a valid and cost-effective way to perform social psychological experiments with large numbers of diverse subjects.

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