The Wharton School

In 1881, American entrepreneur and industrialist Joseph Wharton established the world’s first collegiate school of business at the University of Pennsylvania — a radical idea that revolutionized both business practice and higher education.

Since then, the Wharton School has continued innovating to meet mounting global demand for new ideas, deeper insights, and  transformative leadership. We blaze trails, from the nation’s first collegiate center for entrepreneurship in 1973 to our latest research centers in alternative investments and neuroscience.

Wharton's faculty members generate the intellectual innovations that fuel business growth around the world. Actively engaged with the leading global companies, governments, and non-profit organizations, they represent the world's most comprehensive source of business knowledge.

For more information, see the Research, Directory & Publications site.

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Now showing 1 - 10 of 395
  • Publication
    Evidence-Based Forecasting for Climate Change
    (2013-02-01) Green, Kesten C; Armstrong, J. Scott; Armstrong, J. Scott
    Following Green, Armstrong and Soon’s (IJF 2009) (GAS) naïve extrapolation, Fildes and Kourentzes (IJF 2011) (F&K) found that each of six more-sophisticated, but inexpensive, extrapolation models provided forecasts of global mean temperature for the 20 years to 2007 that were more accurate than the “business as usual” projections provided by the complex and expensive “General Circulation Models” used by the U.N.’s Intergovernmental Panel on Climate Change (IPCC). Their average trend forecast was .007°C per year, and diminishing; less than a quarter of the IPCC’s .030°C projection. F&K extended previous research by combining forecasts from evidence-based short-term forecasting methods. To further extend this work, we suggest researchers: (1) reconsider causal forces; (2) validate with more and longer-term forecasts; (3) adjust validation data for known biases and use alternative data; and (4) damp forecasted trends to compensate for the complexity and uncertainty of the situation. We have made a start in following these suggestions and found that: (1) uncertainty about causal forces is such that they should be avoided in climate forecasting models; (2) long term forecasts should be validated using all available data and much longer series that include representative variations in trend; (3) when tested against temperature data collected by satellite, naïve forecasts are more accurate than F&K’s longer-term (11-20 year) forecasts; and (4) progressive damping improves the accuracy of F&K’s forecasts. In sum, while forecasting a trend may improve the accuracy of forecasts for a few years into the future, improvements rapidly disappear as the forecast horizon lengthens beyond ten years. We conclude that predictions of dangerous manmade global warming and of benefits from climate policies fail to meet the standards of evidence-based forecasting and are not a proper basis for policy decisions.
  • Publication
    Testing Behavioral Hypotheses Using an Integrated Model of Grocery Store Shopping Path and Purchase Behavior
    (2009-10-01) Hui, Sam K; Bradlow, Eric T; Fader, Peter S
    We examine three sets of established behavioral hypotheses about consumers' in-store behavior using field data on grocery store shopping paths and purchases. Our results provide field evidence for the following empirical regularities. First, as consumers spend more time in the store, they become more purposeful—they are less likely to spend time on exploration and more likely to shop/buy. Second, consistent with “licensing” behavior, after purchasing virtue categories, consumers are more likely to shop at locations that carry vice categories. Third, the presence of other shoppers attracts consumers toward a store zone but reduces consumers' tendency to shop there.
  • Publication
    Consumer Shopping and Spending Across Retail Formats
    (2004-04-01) Fox, Edward J; Montgomery, Alan L; Lodish, Leonard
    We present an empirical study of household shop- ping and packaged goods spending across retail for- mats—grocery stores, mass merchandisers, and drug stores. Our study assesses competition be- tween formats and ex- plores how retailers’ as- sortment, pricing, and promotional policies, as well as household demo- graphics, affect shopping behavior. We find that consumer expenditures respond more to varying levels of assortment (in particular at grocery stores) and promotion than price. We also find that households that shop more at mass merchan- disers also shop more in all other formats, sug- gesting that visits to mass merchandisers do not substitute for trips to the grocery store.
  • Publication
    Research Note—User Design of Customized Products
    (2007-03-01) Randall, Taylor; Terwiesch, Christian; Ulrich, Karl
    User design offers tantalizing potential benefits to manufacturers and consumers, including a closer match of products to user preferences, which should result in a higher willingness to pay for goods and services. There are two fundamental approaches that can be taken to user design: parameter-based systems and needs-based systems. With parameter-based systems, users directly specify the values of design parameters of the product. With needs-based systems, users specify the relative importance of their needs, and an optimization algorithm recommends the combination of design parameters that is likely to maximize user utility. Through an experiment in the domain of consumer laptop computers, we show that for parameter-based systems, outcomes, including measures for comfort and fit, increase with the expertise of the user. We also show that for novices, the needs-based interface results in better outcomes than the parameter-based interface.
  • Publication
    The Ombudsman: Are Top Executives Paid Enough? An Evidence-Based Review
    (2013-11-01) Jacquart, Philippe; Armstrong, J. Scott
    Our review of the evidence found that the notion that higher pay leads to the selection of better executives is undermined by the prevalence of poor recruiting methods. Moreover, higher pay fails to promote better performance. Instead, it undermines the intrinsic motivation of executives, inhibits their learning, leads them to ignore other stakeholders, and discourages them from considering the long-term effects of their decisions on stakeholders. Relating incentive payments to executives’ actions in an effective manner is not possible. Incentives also encourage unethical behavior. Organizations would benefit from using validated methods to hire top executives, reducing compensation, eliminating incentive plans, and strengthening stockholder governance related to the hiring and compensation of executives.
  • Publication
    An Experimental Analysis of Learning from Experience about Natural-Hazards
    (2005-01-16) Meyer, Robert; Kunreuther, Howard
    The ability of individuals to learn optimal strategies for mitigation against infrequently-occurring natural hazards is explored. We report the results of two experiments in which participants are faced with the problem of learning the most cost-effective means of protecting against earthquake losses. The experiments utilize dynamic computer simulations in which participants are endowed with homes in virtual communities that are prone to periodic impacts by earthquakes. Participants can invest in measures that potentially mitigate losses from quakes but the effectiveness of these measures is initially uncertain. Over time participants have the opportunity to learn about true effectiveness both by direct experience with simulated earthquakes and by observing the decisions and experiences of other players. The data offer a pessimistic view of learning abilities; not only do participants persist in investing in mitigatin instruments that, in fact, have no ability to lower damage, but they also fail to fully invest in instruments that are highly effective. Among the mechanisms that appeared to impede learning was a tendency to mimic local group norms in investment levels (which are suboptimal) and to prematurely terminate attempts to learn. The paper concludes with a discussion of the implications of the work for both basic research on decision making in low-probability, high-consequence settings as well as prescriptive research in natural-hazard mitigation.
  • Publication
    Measuring Multi-Channel Advertising Effectiveness Using Consumer-Level Advertising Response Data
    (2016-01-01) Zantedeschi, Daniel; Feit, Eleanor M; Bradlow, Eric T
    Advances in data collection have made it increasingly easy to collect information on advertising exposures. However, translating this seemingly rich data into measures of advertising response has proven difficult, largely because of concerns that advertisers target customers with a higher propensity to buy or increase advertising during periods of peak demand. We show how this problem can be addressed by studying a setting where a firm randomly held out customers from each campaign, creating a sequence of randomized field experiments that mitigates (many) potential endogeneity problems. Exploratory analysis of individual holdout experiments shows positive effects for both email and catalog; however, the estimated effect for any individual campaign is imprecise, because of the small size of the holdout. To pool data across campaigns, we develop a hierarchical Bayesian model for advertising response that allows us to account for individual differences in purchase propensity and marketing response. Building on the traditional ad-stock framework, we are able to estimate separate decay rates for each advertising medium, allowing us to predict channel-specific short- and long-term effects of advertising and use these predictions to inform marketing strategy. We find that catalogs have substantially longer-lasting impact on customer purchase than emails. We show how the model can be used to score and target individual customers based on their advertising responsiveness, and we find that targeting the most responsive customers increases the predicted returns on advertising by approximately 70% versus traditional recency, frequency, and monetary value-based targeting.
  • Publication
    Trade-Offs in Fairness and Preference Judgments
    (1993) Ordoñez, Lisa D; Mellers, Barbara A
    At the heart of many debates about distributive justice is the widely assumed trade-off between equality and efficiency (Okun, 1975). In the present chapter, equality refers to the distribution of income within a society. Equality increases whenever income variability is reduced. Efficiency refers to the goods and services that result from a given input – production, physical capital, or human labor. Efficiency increases whenever society produces more from the same input. Trade-offs between equality and efficiency occur because increases in one often lead to decreases in the other. An egalitarian society satisfies basic needs by establishing programs that redistribute wealth. But those programs can reduce efficiency when they introduce bureaucratic waste or diminish financial incentives. A reduction in efficiency can lead to fewer investments, fewer jobs, and declining productivity.
  • Publication
    An Alternative Approach for Eliciting Willingness-to-Pay: A Randomized Internet Trial
    (2007-04-01) Damschroder, Laura J; Ubel, Peter A; Riis, Jason; Smith, Dylan M
    Open-ended methods that elicit willingness-to-pay (WTP) in terms of absolute dollars often result in high rates of questionable and highly skewed responses, insensitivity to changes in health state, and raise an ethical issue related to its association with personal income. We conducted a 2x2 randomized trial over the Internet to test 4 WTP formats: 1) WTP in dollars; 2) WTP as a percentage of financial resource; 3) WTP in terms of monthly payments; and 4) WTP as a single lump-sum amount. WTP as a percentage of financial resources generated fewer questionable values, had better distribution properties, greater sensitivity of health states, and was not associated with income. WTP elicited on a monthly basis also showed promise.
  • Publication
    Putting the Organization on Wheels: Workplace Design at SEI
    (2007-01-01) West, Alfred P; Wind, Jerry Yoram
    When a new employee joins SEI, it is an unusual experience. The new hire is given a map and sent down to a storeroom on the lower floor of the main building. There, the employee is issued a chair and desk, both on wheels, with a computer and phone on the desktop. The map shows where in the complex of nine barn-like buildings on the corporate campus in Oaks, Pennsylvania, the new hire will initially be located. The employee then rolls the desk through the buildings, into the oversized elevators designed for this purpose, past hallways filled with a provocative (and sometimes shocking) collection of emerging contemporary art.