Richard R. Batsell

Experimental analysis of choice

Experimental choice analysis continues to attract academic and applied attention. We review what is known about the design, conduct, analysis, and use of data from choice experiments, and indicate gaps in current knowledge that should be addressed in future research. Design strategies consistent with probabilistic models of choice process and the parallels between choice experiments and real markets are considered. Additionally, we address the issues of reliability and validity. Progress has been made in accounting for differences in reliability, but more research is needed to determine which experiments and response procedures will consistently produce more reliable data for various problems.

The role of insulin resistance in the pathogenesis of atherosclerotic cardiovascular disease: an updated review.

Insulin resistance is the main pathologic mechanism that links the constellation of clinical, metabolic and anthropometric traits with increased risk for cardiovascular disease and type II diabetes mellitus. These traits include hyperinsulinemia, impaired glucose intolerance, endothelial dysfunction, dyslipidemia, hypertension, and generalized and upper body fat redistribution. This cluster is often referred to as insulin resistance syndrome. The progression of insulin resistance to diabetes mellitus parallels the progression of endothelial dysfunction to atherosclerosis leading to cardiovascular disease and its complications. In fact, insulin resistance assessed by homeostasis model assessment (HOMA) has shown to be independently predictive of cardiovascular disease in several studies and one unit increase in insulin resistance is associated with a 5.4% increase in cardiovascular disease risk. This review article addresses the role of insulin resistance as a main causal factor in the development of metabolic syndrome and endothelial dysfunction, and its relationship with cardiovascular disease. In addition to this, we review the type of lifestyle modification and pharmacotherapy that could possibly ameliorate the effect of insulin resistance and reverse the disturbances in insulin, glucose and lipid metabolism.

Impact of a restricted natural language interface on ease of learning and productivity

People process natural language in real time and with very limited short-term memories. This article describes a computational architecture for syntactic performance that also requires fixed finite resources.

Predicting the skilled use of hierarchical menus with the keystroke-level model

This article addresses a key question in the application of Card, Moran, and Newells (1983) keystroke-level model to software in which users specify a command by working through a system of hierarchical menus. For example, to insert a row in Lotus 1-2-3®, the user makes three menu choices: W for worksheet, I for insert, and R for row. In the keystroke-level model, it is assumed that a time-consuming mental operation precedes each command. The question in the application of the keystroke-level model to hierarchical menu systems is whether the keystrokes WIR in the previous example constitute the execution of three commands and thus require three mental operations or whether WIR acts as a single command and requires only one mental operation. Data were collected from four highly experienced Lotus 1-2-3 users as they went about their day-to-day work. Strong evidence that only one mental operation is involved in choosing from a hierarchical menu system was obtained. We hypothesize that the discrepancy of our results from the data of others is due to the fact that our subjects were more experienced. The implications of our findings for the design of menus is discussed.

Consumer Resource Allocation Models at the Individual Level

A methodology for the derivation of individual-level resource allocation functions is described. This methodology can be used to derive individual-level multiattribute preference functions that predict the share of some resource an individual consumer will allocate to competing alternatives. The methodology is illustrated in a pilot application in which subjects estimated the proportion of 100 minutes they would spend listening to different music groups.

The role of lipoprotein-associated phospholipase A2 on cardiovascular disease risk assessment and plaque rupture: a clinical review

During the last several last decades, reduction in lipids has been the main focus to decrease the risk of coronary heart disease (CHD). Several lines of evidence, however, have indicated that lipids account only for the <50% of variability in cardiovascular risk in the United States. Therefore, for better identification of people at high cardiovascular risk, a more effective and complete approach is required. Our understanding of atherosclerosis has shifted from a focal disease resulting in symptoms caused by severe stenosis to a systemic disease distinguished by plaque inflammation with a potential to rupture and thrombosis, turning a substenotic atherosclerotic lesion into a complete occlusive lesion. Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is a novel inflammatory biomarker that can provide much needed information about plaque inflammation and plaque stability. Lp-PLA(2) is among the multiple biomarkers that have been associated with increased CHD risk. In this present work, we review the evidence from previous studies addressing the effect of different therapies on decreasing Lp-PLA(2) and the role of direct Lp-PLA(2) inhibitors. This work also briefly reviews the evidence of Lp-PLA(2) clinical utility as a potential marker of vascular inflammation and formation of rupture prone plaques. Additionally, we also discuss the implication of available evidence in context of current cardiovascular inflammatory biomarkers recommendations and the evidence from epidemiologic studies addressing the relationship of Lp-PLA(2) and risk of cardiovascular disease.

Efficacy of Combination Drug Pulse Therapy in Maintaining Lipid Levels in Patients Intolerant of Daily Statin Use

The objective of this study was to evaluate the efficacy of combination drug pulse therapy in maintaining lipid levels in patients intolerant of a daily dose of statins. Twenty‐three patients, previously receiving aggressive statin therapy, were treated twice weekly with rosuvastatin or atorvastatin in different dosages along with ezetimibe as well as daily doses of bile acid sequestrant for a mean period of 4.5 months. The recommended National Cholesterol Education Program Adult Treatment Panel III goals had already been achieved in 78% of patients (n=18) before starting combination pulse therapy. This combination therapy significantly increased high‐density lipoprotein cholesterol values by 5.82% (t=2.138, P=.044), while the increases in total cholesterol, low‐density lipoprotein cholesterol, triglyceride, and apolipoprotein B levels compared with baseline were not statistically significant. Overall, 3 of 23 patients (13%) discontinued the combination therapy because of muscle‐related symptoms over a mean course of 4.5 months of treatment.

Knowledge of command usage in a spreadsheet program

Knowledge of how software is actually used by people can assist software developers and internal MIS application development personnel to improve the user-interface of existing software, in creating new user interface styles for existing software packages, and to improve the training for personnel using software packages. This article reports results from a study that examined the use of a popular spreadsheet software by 40 experienced users in their work environment. Of the 505 commands that could be used, 18 (3.6%) accounted for over 80% of the usage. More than 50% of the available commands were never used. Most of the command usage was related to creating, maintaining, and printing spreadsheets.

Coherent Probability From Incoherent Judgment

People often have knowledge about the chances of events but are unable to express their knowledge in the form of coherent probabilities. This study proposed to correct incoherent judgment via an optimization procedure that seeks the (coherent) probability distribution nearest to a judges estimates of chance. This method was applied to the chances of simple and complex meteorological events, as estimated by college undergraduates. No judge responded coherently, but the optimization method found close (coherent) approximations to their estimates. Moreover, the approximations were reliably more accurate than the original estimates, as measured by the quadratic scoring rule. Methods for correcting incoherence facilitate the analysis of expected utility and allow human judgment to be more easily exploited in the construction of expert systems.

Lipoprotein-associated phospholipase A2 mass is significantly reduced in dyslipidemic patients treated with lifestyle modification and combination lipid-modifying drug therapy.

Lipoprotein-associated phospholipase A2 (Lp-PLA(2)) mass is a novel inflammatory biomarker. In human blood, Lp-PLA(2) is predominately associated with low-density lipoprotein (LDL). This study examines the ability of lifestyle modification (diet and exercise) and combination lipid therapy to reduce Lp-PLA(2) levels while also determining the relationship between changes in LDL cholesterol and Lp-PLA(2). Thirty dyslipidemic patients who received lifestyle intervention and combination lipid therapy for an average of 6 months were included in these analyses (mean age, 60.9 years); 40% had stable angiographically established coronary artery disease, 40% had the metabolic syndrome, and 70% were men. Drug therapy included omega-3 fish oil, extended-release niacin, colesevelam hydrochloride, and a fixed combination of 10-mg ezetimibe and 40-mg simvastatin. The study revealed a 33% reduction in mean Lp-PLA(2) values (baseline 224.9+/-47.5 vs posttreatment 149.5+/-35.5 ng/mL; P<.001). Significant changes in mean LDL cholesterol from baseline (127.9+/-49.3 vs posttreatment 65.2+/-32.1 mg/dL; P<.001) were also observed. However, regression analysis revealed only a weak positive relationship between changes in LDL cholesterol and Lp-PLA(2) mass (R(2)=0.29; P<.01). Thus, Lp-PLA(2) mass is significantly reduced with lifestyle and combination lipid therapy. Changes in Lp-PLA(2) were only partially explained by the changes observed for LDL cholesterol.