THESIS ABSTRACT The bulk of Internet Service Providers adopt two-part tariff. Two-part tariff means users should pay a fixed rental every month, and pay a varied fee base on their connecting hours. Internet Service Provider group their customers by analyzing customer¡¦s demand level, and provides different group different Pay-Rating. We call this situation Multiple Pay-Rating. If Internet Service Provider provide their customers single Pay-Rating. We call this situation Single Pay-Rating. People always analyze two-part tariff in monopoly market. In this thesis I will analyze two-part tariff in oligopoly market.Then compare with the former, and we will know whether two-part tariff erode customer¡¦s welfare. I will create a differentiate-product demand function base on Logit model, and build two-part tariff oligopoly competition model. Analyze the equilibrium in Single Pay-rating and in Multiple Pay-rating. And I drew several conclusions from the analysis. 1. In oligopoly market structure two-part tariff not necessarily deprive of customer¡¦s welfare. On the contrary if ISP group their customers, customer¡¦s welfare will improve. 2. If there are no differentiation between customers¡¦ utilities, nonlinear pricing will degraded to linear pricing. If customers¡¦ utilities are different, ISP will set up the unit connect fee equal to the unit cost, and the month rental will raised with the increasing differentiation between customers¡¦ utilities. 3. If Internet service provider group their customer and provide them different Pay-rating, the final equilibrium will be symmetrical equilibrium or non-symmetrical equilibrium.

Mediation is used to separate direct and indirect effects of an exposure variable on anoutcome variable. In this thesis, a mediation model is extended to account for censoredmediator and outcome variable. The two-part framework is used to account for thecensoring. The counterfactual based causal effects of this model are derived. A MonteCarlo study is performed to evaluate the behaviour of the causal effects accounting forcensoring, together with a comparison with methods for estimating the causal effectswithout accounting for censoring. The results of the Monte Carlo study show that theeffects accounting for censoring have substantially smaller bias when censoring is present.The proposed effects also seem to have a low cost with unbiased estimates for samplesizes as small as 100 for the two-part mediator model. In the case of limited mediatorand outcome, sample sizes larger than 300 is required for reliable improvements. A smallsensitivity analysis stresses the need of further development of the two-part models.

Remittances significantly affect recipient households’ behavior. Using data from the Jamaican Survey of Living Conditions and the Jamaican Labor Force Survey ( 2001-2007), this dissertation explores the effects of remittances on labor market participation and household expenditures. Jamaica’s proximity to the United States and its diaspora of educated individuals shapes an economy largely dependent on remittances, thus providing an interesting case study. First, we investigate whether remittances alter labor market behavior of married women in remittance-receiving households located in Jamaica. Remittances, the wife’s education, and wages are all treated as endogenous when estimating labor market participation and hours worked. Unlike other studies, we find that after instrumenting for remittances, the outside income has no significant effect on the supply of labor. Second, we assess the extent that remittances alter the consumption pattern of recipient households in Jamaica. Classical theory predicts that total income affects household consumption decisions, but developments in behavioral economics suggest otherwise. The disaggregation of income streams and consumption expenditures provide us with unique insight into household behavior and in particular, spending on items such as food, schooling, and vices. Using Engel curve estimation and the two-part fractional response models, we find that the source of income significantly affects the shares of income spent in specific consumption categories. Recipients, for example, generally spend more of their income on schooling and home production and less at the grocery store. These findings suggest important implications should government look to tax or restrict the flow of remittances.

This dissertation analyzes the men's razor market to examine whether a monopolist can implement price discrimination for the complementary goods. I estimate a demand system for razors using the random coefficient logit model with market level sales data from the Nielsen Store Scanner dataset and individual demographic data from the March CPS. The estimated parameters are used to construct price-cost markups. By comparing the markups of different products, I find evidence that Gillette uses a two-part tariff strategy. This conclusion can be generalized as that of a monopolist setting the prices of tie-in products consistent with a two-part tariff.

Indiana University-Purdue University Indianapolis (IUPUI) / The two-part model (2PM) is the most widely applied modeling and estimation framework in empirical health economics. By design, the two-part model allows the process governing observation at zero to systematically differ from that which determines non-zero observations. The former is commonly referred to as the extensive margin (EM) and the latter is called the intensive margin (IM). The analytic focus of my dissertation is on the development of a general framework for specifying, estimating and drawing inference regarding causally interpretable (CI) effect parameters in the 2PM context. Our proposed fully parametric 2PM (FP2PM) framework comprises very flexible versions of the EM and IM for both continuous and count-valued outcome models and encompasses all implementations of the 2PM found in the literature. Because our modeling approach is potential outcomes (PO) based, it provides a context for clear definition of targeted counterfactual CI parameters of interest. This PO basis also provides a context for identifying the conditions under which such parameters can be consistently estimated using the observable data (via the appropriately specified data generating process). These conditions also ensure that the estimation results are CI. There is substantial literature on statistical testing for model selection in the 2PM context, yet there has been virtually no attention paid to testing the “one-part” null hypothesis. Within our general modeling and estimation framework, we devise a relatively simple test of that null for both continuous and count-valued outcomes. We illustrate our proposed model, method and testing protocol in the context of estimating price effects on the demand for alcohol.

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Indiana University-Purdue University Indianapolis (IUPUI) / The general potential outcomes framework (GPOF) is an essential structure that facilitates clear and coherent specification, identification, and estimation of causal effects. This dissertation utilizes and extends the GPOF, to specify, identify, and estimate causally interpretable (CI) effect parameter (EP) for an outcome of interest that manifests as either a value in a specified subset of the real line or a qualitative event -- a partially qualitative outcome (PQO). The limitations of the conventional GPOF for casting a regression model for a PQO is discussed. The GPOF is only capable of delivering an EP that is subject to a bias due to bad control. The dissertation proposes an outcome measure that maintains all of the essential features of a PQO that is entirely real-valued and is not subject to the bad control critique; the P-weighted outcome – the outcome weighted by the probability that it manifests as a quantitative (real) value. I detail a regression-based estimation method for such EP and, using simulated data, demonstrate its implementation and validate its consistency for the targeted EP. The practicality of the proposed approach is demonstrated by estimating the causal effect of a fully effective policy that bans pregnant women from smoking during pregnancy on a new measure of birth weight. The dissertation also proposes a Generalized Control Function (GCF) approach for modeling and estimating a CI parameter in the context of a fully parametric two-part model (2PM) for a continuous outcome in which the causal variable of interest is continuous and endogenous. The proposed approach is cast within the GPOF. Given a fully parametric specification for the causal variable and under regular Instrumental Variables (IV) assumptions, the approach is shown to satisfy the conditional independence assumption that is often difficult to hold under alternative approaches. Using simulated data, a full information maximum likelihood (FIML) estimator is derived for estimating the “deep” parameters of the model. The Average Incremental Effect (AIE) estimator based on these deep parameter estimates is shown to outperform other conventional estimators. I apply the method for estimating the medical care cost of obesity in youth in the US.

Most symptom measures either implicitly or explicitly distinguish between symptom presence and symptom severity. For example, item 2 on the PHQ-9, a commonly used measure of depressive symptoms, asks respondents to rate how much they have been 'feeling down, depressed, or hopeless.' The response options are 0 (Not at all), 1 (Several Days), 2 (More than half the days), and 3 (Nearly every day). Answering 0 indicates that the symptom is not present, and any response greater than 0 suggests the symptom is present. Higher values indicate higher severity of the symptom. Although the response options distinguish between symptom presence and severity, most users of the PHQ-9 score it by assuming that a 0 (i.e., no symptom), lack of symptoms, is the low end of the severity spectrum. However, clinically, there is often a distinction between experiencing symptoms and how severe any one of those symptoms is. Baldwin and Olsen (2023) developed a sequential item-response theory model that can be used to evaluate whether symptom presence and symptom severity should be separated or considered part of the same construct. We applied the sequential model to 3 datasets, a sample of 6242 participants, containing a variety of measures (e.g., Beck Depression Inventory- Second Edition, State Trait Anxiety Inventory, Penn State Worry Questionnaire). The results indicate that the Two-Part model has best overall fit out of the three models (Two-part, Extreme Response, Unique relationship), suggesting that symptom presence and severity should typically be considered distinct constructs. We discuss the implications for scoring and clinical use of symptom measures in light of our results.

No / Trade credit terms offer firms contractual solutions to informational asymmetries between buyers and sellers. The credit period permits buyers to reduce uncertainty concerning product quality prior to payment, while the seller can reduce uncertainty concerning buyer payment intentions by prescribing payment before/on delivery or through two¿part payment terms and other mechanisms. Variation in trade credit terms also offers firms price discriminating opportunities. This study, drawing on the responses of 700 large firms in the US, UK and Australia, explores trade credit terms through the twin objectives of reducing information asymmetries and discriminatory pricing. Support is found for both theories.

The aerospace industry strives to develop new methods of refining gas turbine engines by increasing power and thermal efficiencies while simultaneously reducing cost. Turbine engines operate under high temperatures and therefore thermal barrier coatings (TBCs) composed of yttria-stabilized zirconia (YSZ) play an important role in improving the performance of the components that make up the engine. Failure of the TBC could lead to catastrophic events, thus requiring consistent and accurate characterization for supplier qualification and production quality assurance. However, due to porosity and the anisotropic behavior of the coating and variability in processing of TBCs, consistent characterization has proven to be extremely challenging. One of the reoccurring issues is the inconsistency in measuring percent porosity, which stems from the difficulty in distinguishing filled pores from damaged, unfilled voids. Sample preparation of TBCs involves sectioning, mounting, grinding, polishing, and characterization. Eliminating variability in characterization begins with mounting which is a critical step to protect the surface integrity and edge retention of the coating during grinding and polishing. The curing kinetics of a slow cure two part epoxy was investigated and the TBC samples were mounted and cured at heating rates of 2, 5, and 10°C/min to 55°C and 70°C. Grinding and polishing procedures simulated industry practices followed by characterization with optical microscopy. Results showed that heating rates of 2°C/min to 55°C and 70°C have the best impregnation properties while uncontrolled or high heating rates of 10°C/min had an increase in the amount of pullouts and lack of infiltration from the epoxy. The curing kinetics of the epoxy needs to be controlled to eliminate the ambiguity of filled and unfilled pores. / Master of Science