How To Pick The Best Regression Equation: A Review And Comparison Of Model Selection Algorithms

This paper reviews and compares twenty-one different model selection algorithms (MSAs) representing a diversity of approaches, including (i) information criteria such as AIC and SIC; (ii) selection of a “portfolio” or best subset of models; (iii) general-to-specific algorithms, (iv) forward-stepwise regression approaches; (v) Bayesian Model Averaging; and (vi) inclusion of all variables. We use coefficient unconditional mean-squared error (UMSE) as the basis for our measure of MSA performance. Our main goal is to identify the factors that determine MSA performance. Towards this end, we conduct Monte Carlo experiments across a variety of data environments. Our experiments show that MSAs differ substantially with respect to their performance on relevant and irrelevant variables. We relate this to their associated penalty functions, and a bias-variance tradeoff in coefficient estimates. It follows that no MSA will dominate under all conditions. However, when we restrict our analysis to conditions where automatic variable selection is likely to be of greatest value, we find that two general-to-specific MSAs, Autometrics, do as well or better than all others in over 90% of the experiments.Model selection algorithms; Information Criteria; General-to-Specific modeling; Bayesian Model Averaging; Portfolio Models; AIC; SIC; AICc; SICc; Monte Carlo Analysis; Autometrics

Parallel Deterministic and Stochastic Global Minimization of Functions with Very Many Minima

The optimization of three problems with high dimensionality and many local minima are investigated under five different optimization algorithms: DIRECT, simulated annealing, Spall’s SPSA algorithm, the KNITRO package, and QNSTOP, a new algorithm developed at Indiana University

Maximal Oxygen Uptake, Sweating and Tolerance to Exercise in the Heat

The physiological mechanisms that facilitate acute acclimation to heat have not been fully elucidated, but the result is the establishment of a more efficient cardiovascular system to increase heat dissipation via increased sweating that allows the acclimated man to function with a cooler internal environment and to extend his performance. Men in good physical condition with high maximal oxygen uptakes generally acclimate to heat more rapidly and retain it longer than men in poorer condition. Also, upon first exposure trained men tolerate exercise in the heat better than untrained men. Both resting in heat and physical training in a cool environment confer only partial acclimation when first exposed to work in the heat. These observations suggest separate additive stimuli of metabolic heat from exercise and environmental heat to increase sweating during the acclimation process. However, the necessity of utilizing physical exercise during acclimation has been questioned. Bradbury et al. (1964) have concluded exercise has no effect on the course of heat acclimation since increased sweating can be induced by merely heating resting subjects. Preliminary evidence suggests there is a direct relationship between the maximal oxygen uptake and the capacity to maintain thermal regulation, particularly through the control of sweating. Since increased sweating is an important mechanism for the development of heat acclimation, and fit men have high sweat rates, it follows that upon initial exposure to exercise in the heat, men with high maximal oxygen uptakes should exhibit less strain than men with lower maximal oxygen uptakes. The purpose of this study was: (1) to determine if men with higher maximal oxygen uptakes exhibit greater tolerance than men with lower oxygen uptakes during early exposure to exercise in the heat, and (2) to investigate further the mechanism of the relationship between sweating and maximal work capacity

Small drill-hole, gas mini-permeameter probe

The distal end of a basic tube element including a stopper device with an expandable plug is positioned in a pre-drilled hole in a rock face. Rotating a force control wheel threaded on the tube element exerts force on a sleeve that in turn causes the plug component of the stopper means to expand and seal the distal end of the tube in the hole. Gas under known pressure is introduced through the tube element. A thin capillary tube positioned in the tube element connects the distal end of the tube element to means to detect and display pressure changes and data that allow the permeability of the rock to be determined

Development and Validation of an Instrument Measuring Determinants of Bystander Intervention to Prevent Sexual Assault: An application of the Reasoned Action Approach

Bystander Intervention (BI) is an evidence-based approach that is considered the gold standard by governmental organizations to reduce sexual assault in college. Few survey instruments are available to measure the predispositions students have towards engaging in BI. Valid and reliable instruments are greatly needed, especially those tailored to BI. The purpose of this study was to develop and validate an instrument based on the reasoned action approach with college students at two U.S. universities. An elicitation of beliefs was accomplished to inform survey items (i.e., behavioral, normative, and control beliefs). Then, an initial draft was developed and sent to an expert panel to establish validity. The final instrument was administered to undergraduate students (n = 291), and further psychometric properties (construct validity and internal consistency reliability) were evaluated. Data were fit into two separate models to evaluate fit. In the first model, a four-factor solution was evaluated (intentions, attitudes, perceived norms, and perceived behavioral control), and while results were modest, the second seven-factor solution model contained a better fit (intentions, instrumental and experiential attitudes, injunctive and descriptive norms, capacity, and autonomy). Researchers and practitioners examining BI in college can use this instrument to measure theory-based determinants of BI to reduce sexual assault

From social contract to 'social contrick' : the depoliticisation of economic policy-making under Harold Wilson, 1974–75

The 1974-79 Labour Governments were elected on the basis of an agreement with the TUC promising a redistribution of income and wealth known as the Social Contract. However, the Government immediately began to marginalise these commitments in favour of preferences for incomes policy and public expenditure cuts, which has led the Social Contract to be described as the 'Social Contrick'. These changes were legitimised through a process of depoliticisation, and using an Open Marxist framework and evidence from the National Archives, the paper will show that the Treasury's exchange rate strategy and the need to secure external finance placed issues of confidence at the centre of political debate, allowing the Government to argue there was no alternative to the introduction of incomes policy and the reduction of public expenditure

Book Reviews

Book Reviews: Overthrow: America's Century of Regime Change From Hawaii to Iraq by Stephen Kinzer ; Longitude and Empire: How Captain Cook's Voyages Changed the World by Brian W. Richardson ; Pacific Encounters: Art & Diversity in Polynesia 1760-1860 by Steven Hooper ; All Men Are Brothers: The Life & Times of Francis Williams Damon by Paul Berry ; Broken Trust: Greed, Mismanagement, & Political Manipulation at America's Largest Charitable Trust by Samuel P. King and Randall W. Roth ; Crowning the Nice Girl: Gender, Ethnicity, and Culture in Hawai'i's Cherry Blossom Festival by Christine R. Yano ; Combat Chaplain: The Personal Story of the World War II Chaplain of the Japanese American 100th Battalion by Israel A. S. Yost ; Hawaiian Volcanoes by Clarence Edward Dutton ; Reworking Race: The Making of Hawaii's Interracial Labor Movement by Moon-Kie Jung ; Islands in a Far Sea: The Fate of Nature in Hawai'i by John L. Culliney

An instrument to measure job satisfaction of nursing home administrators

BACKGROUND: The psychometric properties of the nursing home administrator job satisfaction questionnaire (NHA-JSQ) are presented, and the steps used to develop this instrument. METHODS: The NHA-JSQ subscales were developed from pilot survey activities with 93 administrators, content analysis, and a research panel. The resulting survey was sent to 1,000 nursing home administrators. Factor analyses were used to determine the psychometric properties of the instrument. RESULTS: Of the 1,000 surveys mailed, 721 usable surveys were returned (72 percent response rate). The factor analyses show that the items were representative of six underlying factors (i.e., coworkers, work demands, work content, work load, work skills, and rewards). CONCLUSION: The NHA-JSQ represents a short, psychometrically sound job satisfaction instrument for use in nursing homes