Accuracy in job analysis: toward an inference‐based model

Although the accuracy of job analysis information is critically important, standards for accuracy are not clear. Researchers have recently begun to address various aspects of job analysis accuracy by investigating such things as potential sources of inaccuracy in job analysis as well as attempting to reconceptualize our notions of job analysis accuracy. This article adds to the debate by first discussing how job analysis accuracy has been conceptualized. This points to difficulties in the prevalent ‘true score’ model upon which many of these discussions have been based. We suggest that discussions of job analysis accuracy would benefit from a consideration of the validity of job analysis inferences, as a complement to the more traditional focus on the validity of job analysis data. Toward this end, we develop a model of the inferences made in the job analysis process, outline some of the ways these inference could be tested, and discuss implications of this perspective. Copyright © 2000 John Wiley & Sons, Ltd.     

SPATIAL AND TEMPORAL INFLUENCE OF SOIL FROST ON INFILTRATION AND EROSION OF SAGEBRUSH RANGELANDS1

ABSTRACT: Soil infiltration capacity and interrill erosion are significantly influenced by soil frost on western rangelands which are characterized by cold winters and numerous freeze-thaw cycles. However, little is known about the variable influence of this phenomenon. Infiltration and interrill erosion were measured within a sagebrush-grass plant community during the winter, spring, and summer of 1989. Significant spatial and temporal differences in infiltration capacity and interrill erosion were found for shrub coppice dune and dune interspace soils. Infiltration was generally higher for coppice dune soils compared to interspace soils throughout the year. Infiltration capacity for both soils was lowest early in the year when the soil was frozen or saturated, then increased as the soil dried in the spring and summer. Interrill erosion was consistently lower for coppice dune soils compared to interspace soils. Erosion from interspace soils was greatest during a 19-day period in late winter characterized by diurnal freeze-thaw cycles, saturated surface soil conditions, and soil slaking.     

Sacrococcygeal teratoma: Prenatal diagnosis with elevated alphafetoprotein and acetylcholinesterase in amniotic fluid

A sacrococcygeal teratoma was suspected by ultrasound examination at 24 weeks gestation. The amniotic fluid alphafetoprotein was markedly elevated, as was maternal serum AFP. Gel electrophoresis of amniotic fluid showed an acetylcholinesterase band. Labour began at 25 weeks gestation and the chromosomally normal male fetus was found to have a sacrococcygeal teratoma equal to three-quarters of the weight of the fetus.     

Opportunities and constraints for development and conservation: Teller County/Woodland Park growth management plan

This is the second of three articles prepared to explain the Teller County growth management process. As part of an ongoing growth management process in Teller County, Colorado, opportunities and constraints for development and conservation were identified. The scenic mountain county faces a number of issues because of growth. The recognition of those issues has resulted in the goal to direct future growth to the most appropriate and cost-effective places. To determine those places that are best for new development, thorough ecological inventories were conducted for the entire county as well as for the City of Woodland Park area. From these inventories, environmentally sensitive areas were identified. The environmentally sensitive areas were considered constraints in conducting suitability analyses for a variety of potential land uses. The suitability analyses resulted in the identification of opportunities for future growth in Teller County generally as well as the more specific Woodland Park planning area. This article, like the other two, is part of a reflective analysis by the planners who were involved. Paper 2 in a series 3.     

Ecological planning: A review

Beginning with the passage of the National Environmental Policy Act in 1969, the federal government of the United States has enacted numerous pieces of legislation intended to protect or conserve the environment. Other national governments have also enacted environmental legislation during the past two decades. State and local governments have also adopted policies concerned with environmental planning and management. Multiple laws and overlapping governmental agency responsibilities have confused development and resource management efforts. A comprehensive methodology that integrates the legal mandates and the agency missions into a common and unified framework is needed. Ecological planning offers such a method. Application of the method allows planners and resource managers to better understand the nature and character of the land and/or resource and therefore make better decisions about its appropriate use or management. The steps taken in an ecological planning process—1) goal setting, 2) inventory and analysis of data, 3) suitability analysis, 4) developing alternatives, 5) implementation, 6) administration, and 7) evaluation—are outlined and explained. Hand-drawn overlays and computer programs as techniques for handling ecological planning information are compared. Observations and suggestions for further research are offered.     

Water-based condensation particle counters for environmental monitoring of ultrafine particles

TSI Inc. (Shoreview, MN) has introduced three new water-based condensation particle counters (WCPCS) that were designed to detect airborne particles larger than 2.5 nm (model 3786), 5 nm (model 3785), and either 10 or 20 nm (model 3782). These WCPCs are well suited for real-time, environmental monitoring of number concentration of airborne ultrafine particles. Their unique design incorporates the use of water as the working fluid instead of alcohol. Water is odor free, readily available, and eliminates the problem of water condensation and absorption into alcohol working fluids during operation in humid environments. In this study, the performance of three TSI WCPCs was characterized for several aerosol compositions, including sucrose, salt (NaCl), dioctyl sebacate (DOS), dioctyl phthalate (DOP), emery oil (poly-alpha-olefin), silver, impurity residue particles, and ambient aerosol particles. All particles were size selected using a nano differential mobility analyzer (nano-DMA; model 3085, TSI Inc.) to create monodisperse challenge aerosols. The challenge aerosol was mixed uniformly with clean makeup flow and split into a WCPC and a reference instrument to determine the counting efficiency of the WCPC. For the model 3785 WCPC, the D50 (i.e., the particle diameter with 50% counting efficiency) was determined to be 3.1 nm for salt particles, 4.7 nm for sucrose and ambient particles, 5.6 nm for silver particles, and >50 nm for ultrapure oil particles. The sensitivity to oil droplets increased dramatically (D50 < 10 nm) when the oil was slightly contaminated. The D50 of model 3786 ultrafine water-based CPC (UWCPC) was 2.4 nm for impurity residue particles. The D50 of the model 3782 WCPC was 10.8 (with a nominal setting of 10 nm) or 19.8 nm (with a nominal setting of 20 nm) for sucrose particles. All three WCPCs have response times of less than 2 or 3 sec and are therefore able to detect fast-changing events.     

The international toxicity equivalency factor (I‐TEF) method for estimating risks associated with exposures to complex mixtures of dioxins and related compounds∗

The International Toxicity Equivalency Factor (I‐TEF) method of risk assessment is a revised interim procedure for assessing the risks associated with exposures to complex mixtures of chlorinated dibenzo‐p‐dioxins and dibenzofurans (CDDs and CDFs). This updated scheme was developed by a working group of the North Atlantic Treaty Organization's Committee on the Challenges of Modern Society and has been officially adopted by the U.S. Environmental Protection Agency (EPA), Canada, Ontario Ministry of the Environment, the Nordic countries, the Netherlands, and the United Kingdom. Prior to the development of the I‐TEF method, at least ten slightly different schemes had been used throughout the world which complicated communication among scientists and regulatory agencies concerning the toxicological significance of complex mixtures of CDDs and CDFs. The I‐TEF approach facilitates risk communication internationally by reducing large volumes of analytical data into a single number‐International Toxicity Equivalents (I‐TEQ). As a result, the I‐TEF method represents an improvement in an already useful risk assessment/regulatory tool.     

Mark recapture distance sampling: using acoustics to estimate the fraction of dolphins missed by observers during shipboard line-transect surveys

Environmental and Ecological Statistics - Cetacean abundance estimation often relies on distance sampling methods using shipboard visual line-transect surveys, which assumes that all animals on the...