THE IMPACT OF HUMAN ERROR ON DELIVERING SERVICE QUALITY

This paper opens a new avenue for investigation of quality issues in services. We take the viewpoint that a substantial portion of service failures is the result of human error in the delivery process. Drawing upon the Generic Error Modeling System (gems) from the cognitive science literature, we develop a framework for understanding the role of human error in service failures. An empirical investigation assesses the applicability of this framework to services, identifies which error mechanisms are important sources of service failure, and clarifies how the different roles of customers and providers affect the errors made by each.     

A COMPARISON OF PRODUCTION SCHEDULING POLICIES ON COSTS,SERVICE LEVEL,AND SCHEDULE CHANGES

We consider a single product, single level, stochastic master production scheduling (Mps ) model where decisions are made under rolling planning horizons. Outcomes of interest are cost, service level, and schedule stability. The subject of this research is the Mps control system: the method used in determining the amount of stock planned for production in each time period. Typically, Mps control systems utilize a single buffer stock. Here, two Mps dual-buffer stock systems are developed and tested by simulation. We extend the data envelopment analysis (dea ) methodology to aid in the evaluation of the simulation results, where Dea serves to increase the scope of the experimental design. Results indicate that the dual-buffer control systems outperform existing policies.     

The Auditor's Going-Concern Disclosure as a Self-Fulfilling Prophecy: A Discrete-Time Survival Analysis*

The question of how an auditor's going-concern disclosure affects a client's future operations has long troubled the auditing profession. In an attempt to provide further understanding of this issue, we introduce Discrete-Time Survival Analysis (DTSA) to examine the aftermath of 231 first-time going-concern disclosures on clients' subsequent continuance. DTSA represents a significant refinement over traditional ordinary least squares (OLS) and logistic (LOGIT) regression in that it provides not only a probability estimate, but also an estimate of the timing of the event occurrence. The addition of this extra dimension (event timing) aids decision makers by providing more complete information about event probabilities. Consistent with the “self-fulfilling prophecy effect,” the risk profiles developed from DTSA indicate that the first year subsequent to the initial going-concern disclosure was the most dangerous in terms of risk of bankruptcy. However, after the first year, the incidence of bankruptcy decreases significantly. Thus, DTSA is able to provide a richer perspective on this perplexing issue than previously considered.     

Agriculture,Pesticide Use,and Economic Development: A Global Examination (1990–2014)

Modern agricultural production typically requires large quantities of chemical pesticides, a potential source of both environmental and human harm. Previous social science research has suggested that environmental problems such as those associated with pesticide use may begin to decline at higher levels of economic development. Using fixed effects models, we examine whether this possible relationship holds within nations and over time. This study draws on data from the World Bank as well as pesticide use data from the Food and Agriculture Organization of the United Nations to examine the relationship between pesticide use and economic development within nations from 1990 to 2014. The findings are considered from theoretical perspectives in environmental sociology on the drivers of environmental impacts: the treadmill of production theory, structural human ecology, ecological modernization theory, and the environmental Kuznets curve hypothesis. The results of this study show a positive relationship between economic development and pesticide consumption over time, with no decline in use at higher levels of economic development. Thus, they generally support the claims made by treadmill of production and structural human ecology.     

Before,Now, and After: Assessing Hurricane Katrina Relief

We assess governmental and non-governmental responses to disasters using primary data of Hurricane Katrina survivors along the Mississippi Gulf Coast. Non-governmental sources include nonprofit relief groups, faith-based organizations, and survivors’ self-identified social networks. We assess the impact of these governmental and non-governmental relief efforts on survivors’ economic, psychological, physical, and social effects from the disaster. Our results show that social isolation significantly increases perceptions of disaster disturbance and decreases perceived rates of disaster relief. Additionally, survivors perceive that social networks provide greater sources of psychological, financial and social disaster relief than government sources. However, survivors’ social networks decay sharply in the immediate aftermath of a disaster, and they do not appear to fully recover a year from the disaster. These social networks themselves are not fully resilient to a disaster.

The Rheumatoid Arthritis Drug Development Model: a case study in Bayesian clinical trial simulation

The development of a new drug is a major undertaking and it is important to consider carefully the key decisions in the development process. Decisions are made in the presence of uncertainty and outcomes such as the probability of successful drug registration depend on the clinical development programmme. The Rheumatoid Arthritis Drug Development Model was developed to support key decisions for drugs in development for the treatment of rheumatoid arthritis. It is configured to simulate Phase 2b and 3 trials based on the efficacy of new drugs at the end of Phase 2a, evidence about the efficacy of existing treatments, and expert opinion regarding key safety criteria. The model evaluates the performance of different development programmes with respect to the duration of disease of the target population, Phase 2b and 3 sample sizes, the dose(s) of the experimental treatment, the choice of comparator, the duration of the Phase 2b clinical trial, the primary efficacy outcome and decision criteria for successfully passing Phases 2b and 3. It uses Bayesian clinical trial simulation to calculate the probability of successful drug registration based on the uncertainty about parameters of interest, thereby providing a more realistic assessment of the likely outcomes of individual trials and sequences of trials for the purpose of decision making. In this case study, the results show that, depending on the trial design, the new treatment has assurances of successful drug registration in the range 0.044–0.142 for an ACR20 outcome and 0.057–0.213 for an ACR50 outcome. Copyright © 2009 John Wiley & Sons, Ltd.     

Analytic bounds on causal risk differences in directed acyclic graphs involving three observed binary variables

We apply a linear programming approach which uses the causal risk difference (R_DC)$(R{D}_C)$ as the objective function and provides minimum and maximum values that R_DC$R{D}_C$ can achieve under any set of linear constraints on the potential response type distribution. We consider two scenarios involving binary exposure X, covariate Z and outcome Y. In the first, Z is not affected by X, and is a potential confounder of the causal effect of X on Y. In the second, Z is affected by X and intermediate in the causal pathway between X and Y. For each scenario we consider various linear constraints corresponding to the presence or absence of arcs in the associated directed acyclic graph (DAG), monotonicity assumptions, and presence or absence of additive-scale interactions. We also estimate Z-stratum-specific bounds when Z is a potential effect measure modifier and bounds for both controlled and natural direct effects when Z is affected by X  . In the absence of any additional constraints deriving from background knowledge, the well-known bounds on R_Dc$R{D}_c$ are duplicated: -Pr(Y≠X)?R_DC?Pr(Y=X)$-\mathit{Pr}(Y\ne X)?R{D}_C?\mathit{Pr}(Y=X)$. These bounds have unit width, but can be narrowed by background knowledge-based assumptions. We provide and compare bounds and bound widths for various combinations of assumptions in the two scenarios and apply these bounds to real data from two studies.     

Hitting and missing targets by ambulance services for emergency calls: effects of different systems of performance measurement within the UK

Summary.  Following devolution, differences developed between UK countries in systems of measuring performance against a common target that ambulance services ought to respond to 75% of calls for what may be immediately life threatening emergencies (category A calls) within 8 minutes. Only in England was this target integral to a ranking system of 'star rating', which inflicted reputational damage on services that failed to hit targets, and only in England has this target been met. In other countries, the target has been missed by such large margins that services would have been publicly reported as failing, if they had been covered by the English system of star ratings. The paper argues that this case-study adds to evidence from comparisons of different systems of hospital performance measurement that, to have an effect, these systems need to be designed to inflict reputational damage on those that have performed poorly; and it explores implications of this hypothesis. The paper also asks questions about the adequacy of systems of performance measurement of ambulance services in UK countries.     

INQUIRY METHOD,GOAL DIFFICULTY,AND CONTEXT EFFECTS ON PERFORMANCE

The decision-making in this study compares the performance of the dialectical inquiry (DI) and the devil's advocate (DA) techniques. In addition, the task was structured to include three levels of goal difficulty and three decision-making contexts. Over all contexts, there were no significant differences between the DI and DA methods. When the DI technique was employed, however, the context of the decision appeared to be an important factor. The goal-difficulty factor was associated with significant effects on decision quality only when individuals were divided according to their perceptions of goal relevancy and meaning. Finally, the order in which the contexts were considered was important.     

A comparison of soil organic carbon stocks between residential turf grass and native soil

A central principle in urban ecological theory implies that in urbanized landscapes anthropogenic drivers will dominate natural drivers in the control of soil organic carbon storage (SOC). To assess the effect of urban land-use change on the storage of SOC, we compared SOC stocks of turf grass and native cover types of two metropolitan areas (Baltimore, MD, and Denver, CO) representing climatologically distinct regions in the United States. We hypothesized that introducing turf grass and management will lead to higher SOC densities in the arid Denver area and lower densities in the mesic Baltimore area relative to native cover types. Moreover, differences between turf grass soils will be less than differences between the native soils of each metropolitan region. Within Baltimore, turf grass had almost a 2-fold higher SOC density at 0- to 1-m and 0- to 20-cm depths than in rural forest soils, whereas there were no differences with soils of urban forest remnants. Moreover, urban forest remnants had more than 70% higher SOC densities than rural forest soils. Within Denver, turf grass (>25 years of age) had more than 2-fold higher SOC densities than in shortgrass steppe soils, while having similar densities to Baltimore turf grass soils. By contrast, the native soils of Baltimore were almost 2-fold higher than the native steppe grass soils of Denver using SOC densities of remnant forests as representative of native soils in the Baltimore region. These results supported our hypothesis that turf grass systems will be similar in SOC densities across regional variations in climate, parent material, and topography. These similarities are apparently due to greater management efforts in the Denver region to offset the constraint of climate, i.e., anthropogenic factors (management supplements) overwhelmed native environmental factors that control SOC storage.