Browsing by Author "Wu, Jisong"

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    The effect of sugar-sweetened beverage consumption on childhood obesity - causal evidence
    (2016-05-18) Yang, Yan; Terza, Joseph V.; Courtemanche, Charles; Jung, Haeil; Mak, Henry Y.; Wu, Jisong
    Communities and States are increasingly targeting the consumption of sugar sweetened beverages (SSBs), especially soda, in their efforts to curb childhood obesity. However, the empirical evidence based on which policy makers design the relevant policies is not causally interpretable. In the present study, we suggest a modeling framework that can be used for making causal estimation and inference in the context of childhood obesity. This modeling framework is built upon the two-stage residual inclusion (2SRI) instrumental variables method and have two levels – level one models children’s lifestyle choices and level two models children’s energy balance which is assumed to be dependent on their lifestyle behaviors. We start with a simplified version of the model that includes only one policy, one lifestyle, one energy balance, and one observable control variable. We then extend this simple version to be a general one that accommodates multiple policy and lifestyle variables. The two versions of the model are 1) first estimated via the nonlinear least square (NLS) method (henceforth NLS-based 2SRI); and 2) then estimated via the maximum likelihood estimation (MLE) method (henceforth MLE-based 2SRI). Using simulated data, we show that 1) our proposed 2SRI method outperforms the conventional method that ignores the inherent nonlinearity [the linear instrumental variables (LIV) method] or the potential endogeneity [the nonlinear regression (NR) method] in obtaining the relevant estimators; and 2) the MLE-based 2SRI provides more efficient estimators (also consistent) compared to the NLS-based one. Real data analysis is conducted to illustrate the implementation of 2SRI method in practice using both NLS and MLE methods. However, due to data limitation, we are not able to draw any inference regarding the impacts of lifestyle, specifically SSB consumption, on childhood obesity. We are in the process of getting better data and, after doing so, we will replicate and extend the analyses conducted here. These analyses, we believe, will produce causally interpretable evidence of the effects of SSB consumption and other lifestyle choices on childhood obesity. The empirical analyses presented in this dissertation should, therefore, be viewed as an illustration of our newly proposed framework for causal estimation and inference.
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    Specification and estimation of the price responsiveness of alcohol demand: a policy analytic perspective
    (2016-01-13) Devaraj, Srikant; Tezra, Joseph V.; Antwi, Yaa Akosa; Jones, Josette; Wu, Jisong
    Accurate estimation of alcohol price elasticity is important for policy analysis – e.g.., determining optimal taxes and projecting revenues generated from proposed tax changes. Several approaches to specifying and estimating the price elasticity of demand for alcohol can be found in the literature. There are two keys to policy-relevant specification and estimation of alcohol price elasticity. First, the underlying demand model should take account of alcohol consumption decisions at the extensive margin – i.e., individuals' decisions to drink or not – because the price of alcohol may impact the drinking initiation decision and one's decision to drink is likely to be structurally different from how much they drink if they decide to do so (the intensive margin). Secondly, the modeling of alcohol demand elasticity should yield both theoretical and empirical results that are causally interpretable. The elasticity estimates obtained from the existing two-part model takes into account the extensive margin, but are not causally interpretable. The elasticity estimates obtained using aggregate-level models, however, are causally interpretable, but do not explicitly take into account the extensive margin. There currently exists no specification and estimation method for alcohol price elasticity that both accommodates the extensive margin and is causally interpretable. I explore additional sources of bias in the extant approaches to elasticity specification and estimation: 1) the use of logged (vs. nominal) alcohol prices; and 2) implementation of unnecessarily restrictive assumptions underlying the conventional two-part model. I propose a new approach to elasticity specification and estimation that covers the two key requirements for policy relevance and remedies all such biases. I find evidence of substantial divergence between the new and extant methods using both simulated and the real data. Such differences are profound when placed in the context of alcohol tax revenue generation.
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    Two essays on nonprofit finance
    (2016-05-06) Qu, Heng; Steinberg, Richard S.; Konrath, Sara; Ottoni-Wilhelm, Mark; Wu, Jisong; Greenlee, Janet
    This dissertation consists of two essays on nonprofit finance. Nonprofit finance concerns obtaining and managing financial resources to support the social purposes of nonprofit organizations. A unique feature of nonprofit finance is that nonprofits derive revenue from a variety of sources. Nonprofit finance thus involves answering two fundamental questions: What is the optimal combination of revenue sources that supports a nonprofit to achieve its mission? Where and how to obtain the revenue sources? The two dissertation essays address these two questions respectively. The first essay, titled “Modern Portfolio Theory and the Optimization of Nonprofit Revenue Mix,” is among the first to properly apply modern portfolio theory (MPT) from corporate finance to nonprofit finance. By analyzing nonprofit tax return data, I estimate the expected return and risk characteristics for five nonprofit revenue sources as well as the correlations among these returns. I use the estimates to identify the efficient frontiers for nonprofits in different industries, based on which nonprofit managers can select an optimal portfolio that can minimize the risk given a preferred level of service provision or maximize the return given a level of risk. The findings also pose a challenge to the predominant approach used in previous nonprofit finance studies (Herfindahl-Hirschman Index) and suggest that MPT is theoretically and practically more helpful in guiding nonprofit revenue management. The second essay, titled “Charitable Giving in Nonprofit Service Associations: Identities, Incentives, and Gender Differences,” concerns nonprofit resource attainment, specifically, how do decisionmaking contexts and framing affect donations. Membership in a service club is characterized by two essential elements: members’ shared interest in the club’s charitable mission; and private benefits that often come as a result of social interactions with other members, such as networking, fellowship, and fun. A laboratory experiment was designed to examine 1) whether membership in a service club makes a person more generous and 2) the effect of service club membership—stressing either the service or socializing aspects—on individual support for collective goods. The study finds that female individuals are the least generous when they are reminded of the socializing aspect of service-club membership.