Six of one, half dozen of the other: Expanding and contracting numerical dimensions produces preference reversals

ABSTRACT-The scales used to describe the attributes of different choice options are usually open to alternative expressions, such as inches versus feet or minutes versus hours. More generally, a ratio scale can be multiplied by an arbitrary factor (e.g., 12) while preserving all of the information it conveys about different choice alternatives. We propose that expanded scales (e.g., price per year) lead decision makers to discriminate between choice options more than do contracted scales (e.g., price per month) because they exaggerate the difference between options on the expanded attribute. Two studies show that simply increasing the size of an attribute's scale systematically changes its weight in both multiattribute preferences and willingness to pay: Expanding scales for one attribute shifts preferences to alternatives favored on that attribute. In the cult classic This Is Spinal Tap, Nigel points out to the director that the dials on the band's amplifiers are numbered all the way to 11: ''You see, most blokes will be playing at 10. You're on 10, all the way up, all the way up. . . . Where can you go from there? Nowhere. What we do, is if we need that extra push over the cliff. . . . Eleven. One louder.'' The director asks, ''Why don't you just make 10 louder and make 10 be the top number, and make that a little louder?'' Nigel thinks for a bit and replies, ''These go to 11.'' This arbitrary use of scales is not limited to comedy. Consumer Reports rates cars along six attributes. Most attributes are described on 5-point scales, but the overall test score is expressed on a 100-point scale. Will this difference in scales affect which car consumers prefer? It should not. After all, a 5-point scale can easily be converted to a 100-point scale, and vice versa (a fact that Nigel misses). More generally, a scale with ratio properties can be converted from one scale to another by multiplying the original values by some constant factor without changing the information provided by the scale. Thus, a product that is superior to another by 20 points on a 100-point scale is still superior by the same proportion if the information is expressed as a 1-point difference on a 5-point scale. Nevertheless, this trivial transformation seems psychologically consequential. The expanded scale highlights the difference between the two choice options, making it potentially easier to discriminate between them. In contrast, the contracted scale minimizes the difference. Consider a recent demonstration of currency effects. Our argument parallels past findings on risk and ratio judgments. For example, Yamagishi (1997) has shown that people judge ratios expressed with large numerators and denominators (1,286/10,000) as riskier than larger ratios expressed with small numerators and denominators (24.14/100). Stone, Yates, and Parker (1997) were able to exaggerate such effects by putting the 1074 Volume 20-Number 9 Copyright r 2009 Association for Psychological Science information in graphs that made differences in numerators even more salient. Similarly, We believe that previous research on denominator neglect STUDY 1: PREFERENCES AND CHOICE In Study 1, we used a choice paradigm to test participants' preference for options that entail trade-offs across attributes. We predicted that participants would more strongly prefer the option that dominates on an attribute that is expanded. We created two choice sets. The first scenario presented cell-phone plans that varied in cost and number of dropped calls. This scenario contained a strong manipulation such that, when one attribute was expanded, the other was contracted. The second scenario presented movie-rental plans, in which we manipulated the expansion of one attribute (new movies per period of time) while leaving the other attribute (cost) untouched. We predicted that, in both scenarios, preference would increase for the option that was superior on an expanded attribute, causing preference reversal to arise between conditions. Method One hundred six University of Michigan undergraduates completed this study as part of a course requirement. The first scenario (cell-phone plans) asked participants to evaluate cellular phone plan options described in terms of number of dropped calls and cost. Number of dropped calls was either on an expanded scale (dropped calls per 1,000 calls) or a contracted scale (dropped calls per 100 calls). Price was also described either on an expanded scale (price per year) or a contracted scale (price per month). When one attribute was presented as expanded, the other was presented as contracted, thus creating two conditions (see The second scenario (movie rentals) tested discriminability by varying the expansion of only one attribute. Participants evaluated two movie-rental plans that were described in terms of new movie availability and price (see For both scenarios, participants indicated their preference for Plan A versus Plan B on a 7-point scale (1 5 strongly prefer plan A, 4 5 indifferent, 7 5 strongly prefer plan B). Note. Participants evaluated cell-phone plans described in terms of number of dropped calls and cost. Number of dropped calls was either on an expanded scale (dropped calls per 1,000 calls) or on a contracted scale (dropped calls per 100 calls). Price was also described either on an expanded scale (price per year) or on a contracted scale (price per month). In Condition 1, the number of dropped calls was presented on a contracted scale, and price was given on an expanded scale. In Condition 2, the number of dropped calls was presented on an expanded scale, and price was given on a contracted scale. Volume 20-Number 9 1075 Katherine A. Burson, Richard P. Larrick, and John G. Lynch, Jr. Results and Discussion An independent-samples t test showed a significant shift in plan preference based on attribute expansion for both scenarios. For the first scenario, preferences favored Plan B (the plan that was superior on price) when price was expanded and the number of dropped calls was contracted (M 5 4.45). However, preferences favored Plan A (the plan that was superior on the number of dropped calls) when the number of dropped calls was expanded and price was contracted (M 5 3.08), t(104) 5 À3.60, p < .001, d 5 0.706. We converted these data to choice proportions to test for preference reversals. Plan B was preferred when it was described as having a lower price per year but more dropped calls per 100 than Plan A (53% vs. 31%, respectively). 1 However, Plan A was preferred when it was described as having fewer dropped calls per 1,000 but a higher price per month than Plan B (69% vs. 23%, respectively); w 2 (1, N 5 106) 5 13.93, p < .001, j c 5 .363 for the linear contrast of the ordinal choice categories between conditions. For the second scenario, participants favored the superior plan for new movies (Plan B) more when new movies were expanded (M 5 4.33) than when they were contracted (M 5 3.38), t(104) 5 2.16, p 5 .033, d 5 0.424. A test of choice proportions showed that 56% of participants preferred Plan B when number of new movies was expanded to a yearly scale, compared to 38% who preferred Plan A. Contracting number of new movies to a weekly scale resulted in 33% preferring Plan B and 57% preferring Plan A, a significant reversal for the linear contrast of the ordinal choice categories, w The results of Study 1 show that attribute expansion increases preference for the alternative favored on an expanded attribute, despite the fact that the relative differences between alternatives remained the same. STUDY 2: PRICING In this experiment, we modified the second scenario of Study 1 to create a matching paradigm in order to determine participants' valuation of options that entail a trade-off across attributes (e.g., We manipulated both attribute expansion and product valence. Valence was manipulated by presenting the product as either better or worse than the average plan. We predicted that valence would interact with attribute expansion: The difference in willingness to pay for the above-average plan versus the below-average plan would be greater when framed as movies per year (expanded) rather than movies per week (contracted). Method Sixty-three University of Michigan students completed this 2 (attribute expansion: expanded vs. contracted) Â 2 (product valence: above vs. below average) design study in combination with other materials and were paid $8 for their participation. Participants were asked to evaluate two movie-rental plans, as in the second scenario in Study 1. One plan was labeled the average plan and the other was the target plan. Price was provided only for the average plan. Half of the participants evaluated the two movie-rental plans described in terms of new movies per week (i.e., the contracted attribute). The other participants evaluated the two plans described in terms of new movies per year (i.e., the expanded attribute). These plans are presented i

Idiopathic interstitial pneumonia: Do community and academic physicians agree on diagnosis?

Rationale: Treatment and prognoses of diffuse parenchymal lung diseases (DPLDs) varies by diagnosis. Obtaining a uniform diagnosis among observers is difficult. Objectives: Evaluate diagnostic agreement between academic and community-based physicians for patients with DPLDs, and determine if an interactive approach between clinicians, radiologists, and pathologists improved diagnostic agreement in community and academic centers. Methods: Retrospective review of 39 patients with DPLD. A total of 19 participants reviewed cases at 2 community locations and 1 academic location. Information from the history, physical examination, pulmonary function testing, high-resolution computed tomography, and surgical lung biopsy was collected. Data were presented in the same sequential fashion to three groups of physicians on separate days. Measurements and Main Results: Each observer’s diagnosis was coded into one of eight categories. A statistic allowing formultiple raters was used to assess agreement in diagnosis. Interactions between clinicians, radiologists, and pathologists improved interobserver agreement at both community and academic sites; however, final agreement was better within academic centers (Kappa= 0.55–0.71) than within community centers (Kappa=0.32–0.44). Clinically significant disagreement was present between academic and communitybased physicians (Kappa=0.11–0.56). Community physicians were more likely to assign a final diagnosis of idiopathic pulmonary fibrosis compared with academic physicians. Conclusions: Significant disagreement exists in the diagnosis of DPLD between physicians based in communities compared with those in academic centers. Wherever possible, patients should be referred to centers with expertise in diffuse parenchymal lung disorders to help clarify the diagnosis and provide suggestions regarding treatment options.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/91941/1/2007 AJRCCM Idiopathic interstitial pneumonia - Do community and academic physicians agree on diagnosis.pd

Non-emphysematous chronic obstructive pulmonary disease is associated with diabetes mellitus

Abstract Background Chronic obstructive pulmonary disease (COPD) has been classically divided into blue bloaters and pink puffers. The utility of these clinical subtypes is unclear. However, the broader distinction between airway-predominant and emphysema-predominant COPD may be clinically relevant. The objective was to define clinical features of emphysema-predominant and non-emphysematous COPD patients. Methods Current and former smokers from the Genetic Epidemiology of COPD Study (COPDGene) had chest computed tomography (CT) scans with quantitative image analysis. Emphysema-predominant COPD was defined by low attenuation area at -950 Hounsfield Units (LAA-950) ≥10%. Non-emphysematous COPD was defined by airflow obstruction with minimal to no emphysema (LAA-950 < 5%). Results Out of 4197 COPD subjects, 1687 were classified as emphysema-predominant and 1817 as non-emphysematous; 693 had LAA-950 between 5–10% and were not categorized. Subjects with emphysema-predominant COPD were older (65.6 vs 60.6 years, p < 0.0001) with more severe COPD based on airflow obstruction (FEV1 44.5 vs 68.4%, p < 0.0001), greater exercise limitation (6-minute walk distance 1138 vs 1331 ft, p < 0.0001) and reduced quality of life (St. George’s Respiratory Questionnaire score 43 vs 31, p < 0.0001). Self-reported diabetes was more frequent in non-emphysematous COPD (OR 2.13, p < 0.001), which was also confirmed using a strict definition of diabetes based on medication use. The association between diabetes and non-emphysematous COPD was replicated in the ECLIPSE study. Conclusions Non-emphysematous COPD, defined by airflow obstruction with a paucity of emphysema on chest CT scan, is associated with an increased risk of diabetes. COPD patients without emphysema may warrant closer monitoring for diabetes, hypertension, and hyperlipidemia and vice versa. Trial registration Clinicaltrials.gov identifiers: COPDGene NCT00608764 , ECLIPSE NCT00292552 .http://deepblue.lib.umich.edu/bitstream/2027.42/109496/1/12890_2014_Article_599.pd

Search for rare quark-annihilation decays, B --> Ds(*) Phi

We report on searches for B- --> Ds- Phi and B- --> Ds*- Phi. In the context of the Standard Model, these decays are expected to be highly suppressed since they proceed through annihilation of the b and u-bar quarks in the B- meson. Our results are based on 234 million Upsilon(4S) --> B Bbar decays collected with the BABAR detector at SLAC. We find no evidence for these decays, and we set Bayesian 90% confidence level upper limits on the branching fractions BF(B- --> Ds- Phi) Ds*- Phi)<1.2x10^(-5). These results are consistent with Standard Model expectations.Comment: 8 pages, 3 postscript figues, submitted to Phys. Rev. D (Rapid Communications