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Open Access Publications from the University of California

The Paul Merage School of Business combines the academic strengths and best traditions of the University of California with the cutting-edge, entrepreneurial spirit of Orange County. The School's thematic approach to business education is: sustainable growth through strategic innovation.

Cover page of Achieving Excellence for California’s Freight System: Developing Competitiveness and Performance Metrics; Incorporating Sustainability, Resilience, and Workforce Development

Achieving Excellence for California’s Freight System: Developing Competitiveness and Performance Metrics; Incorporating Sustainability, Resilience, and Workforce Development

(2022)

This study explores the question of whether California's freight system is staying competitive with other US regions. A novel analytical framework compares supply chain performance metrics across multiple US states and regions for seaports, airports, highways, freight rail service, and distribution centers by combining the Performance Evaluation Matrix (PEM), Competitive Position Matrix (CPM), and Business Process Management (BPM) approaches. Analysis of industry data and responses from structured interviews with 30 freight industry experts across 5 transportation sectors suggests that California's freight system is competitive for seaports, airports, and freight rail; however, highways and distribution centers have room for improvement with respect to travel time reliability and operation costs, and California should prioritize infrastructure investments here. To stay competitive with the Texas and North East regions, state investments could also expand seaport container terminals and air cargo handling facilities, improve intermodal port connections and management of flows of chassis, container trucks, empty containers to ameliorate cargo backlogs and congestion on highways, at the ports, and at warehouses. The state could also invest in inland ports, transporting goods by rail directly from seaports to the Inland Empire or Central Valley.

Cover page of Undergraduate support for university smoke-free and vape-free campus policies and student engagement: a quasi-experimental intervention.

Undergraduate support for university smoke-free and vape-free campus policies and student engagement: a quasi-experimental intervention.

(2022)

BackgroundCollege campuses have policies restricting smoking/vaping on campus. Previous studies involving mostly European-American students showed smoking prevalence declines following implementation of such policies.ObjectiveTo evaluate a social media campaign promotive of stronger campus support for an existing campus no-smoking/no-vaping policy where most (∼75%) of the undergraduates were non-European-American. A demographically comparable university served as a no-intervention control.ParticipantsTarget was 200 random intercept surveys at each university during fall 2016, spring 2017. Of 800 respondents, 681 were undergraduates.MethodsBaseline and post-intervention surveys assessed awareness of and support for campus-wide smoke-free/vape-free policies. Staged smoke-free/vape-free policy violations assessed students' propensity to intervene in support of the policy.ResultsRespondent support for the no-smoking/no-vaping policy did not change.ConclusionsThe social media campaign and Policy Ambassadors program did not increase support for the campus no-smoking/no-vaping policy. Most (∼90%) respondents agreed that the campus no-smoking/no-vaping policy was important for public health.

Outcomes of COVID-19 adults managed in an outpatient versus hospital setting.

(2022)

Introduction

The coronavirus disease 2019 (COVID-19) pandemic continues to spread globally and as of February 4, 2021, there are more than 26 million confirmed cases and more than 440,000 deaths in the United States (US). A top priority of the Centers for Disease Control and Prevention (CDC) is to identify risk factors for severe COVID-19 illness. The objective of this study was to analyze the characteristics and outcomes of COVID-19 adults who were managed in an outpatient setting compared to patients who required hospitalization at US academic centers.

Methods

Using the Vizient clinical database, Discharge records of adults with a diagnosis of COVID-19 between March 1, 2020 and January 31, 2021 were reviewed. Outcome measures included demographics, characteristics, rate of hospitalization, and mortality, and data were analyzed based on inpatient versus outpatient management.

Results

Among COVID-19 adults, 1,360,078 patients were managed in an outpatient setting while 545,635 patients required hospitalization. Compared to hospitalized COVID-19 adults, COVID-19 adults who were managed in an outpatient setting were more likely to be female (56.1% vs 47.5%, p <0.001), white (57.7% vs 54.8%, p <0.001), within younger age group of 18-50 years (p<0.001) and have lower rate of comorbidities. Mortality was significantly lower in outpatient group compared to hospitalized group (0.2% vs 12.2%, respectively, p <0.01%). For outpatient group, mortality increased with increasing age group: 0.02% (52 of 295,112) for patients 18-30 years and 1.2% (1,373 of 117,866) for patients >75 years. The rate of hospitalization was lowest for age group 18-30 years at 10.6% (35,607 of 330,719) and highest for age group >75 years at 56.1% (150,381 of 268,247).

Conclusion

This analysis of US academic centers showed that 28.6% of COVID-19 adults who sought care at one of the hospitals reporting data to the Vizient clinical database required in-patient treatment. The rate of hospitalization in our study was lowest for the youngest age group of 18-30 years and highest for age group >75 years. Beside older age, other factors associated with outpatient management included female gender, white race, and having commercial insurance.

Cover page of The Decreasing Trend in US Cash Effective Tax Rates: The Role of Growth in Pre-Tax Income

The Decreasing Trend in US Cash Effective Tax Rates: The Role of Growth in Pre-Tax Income

(2021)

ABSTRACT We develop a linear corporate tax function where taxes paid are regressed on pre-tax income and an intercept. We show that if the intercept is positive, cash ETRs are a convex function of pre-tax income. We present large-sample evidence consistent with this ETR convexity. Thus, although firms may have stable linear tax functions (i.e., constant parameters in the linear tax model) representing stable tax avoidance behavior, ETRs can change over time because of growth in pre-tax income. Consequently, simply examining changes (or differences) in cash ETRs is nondiagnostic about whether tax avoidance has changed over time (or differs across firms). We illustrate our argument by showing that all of the observed downward trend in cash ETRs documented by Dyreng et al. (2017) can be explained by growth in pre-tax income. The wholesale concern about increased tax avoidance over time might be overstated. Data Availability: Data are available from the public sources cited in the text. JEL Classifications: G39; H20; H25; H26.

Cover page of Making Theoretically Informed Choices in Specifying Panel-Data Models

Making Theoretically Informed Choices in Specifying Panel-Data Models

(2021)

We argue that in analyzing panel-data econometric models, researchers rely excessively on statistical criteria to determine model specification, treating it primarily as a matter of statistical inference. This inferential emphasis is most obvious in the common practice of using statistical tests (e.g., the Hausman test) to choose between fixed- and random-effects specifications, often ignoring the assumptions underpinning these tests. For instance, the Hausman test depends on the true within-panel (longitudinal) and between-panel (cross-sectional) parameters being equal. This assumption is often not justified, because longitudinal and cross-sectional variances and covariances may manifest different underpinning mechanisms. In addition to different mechanisms often resulting in different variables determining within and between effects, within and between variables may also have different meanings. To help researchers make theoretically informed choices, we formulate five questions that can help researchers think of model specification in a theoretically rigorous way. We examine these issues with examples from both the general management and operations management research. Importantly, we argue that addressing the questions regarding model specification must involve primarily theoretical and contextual judgement, not statistical tests.

Cover page of Perceived Costs versus Actual Benefits of Demographic Self-Disclosure in Online Support Groups

Perceived Costs versus Actual Benefits of Demographic Self-Disclosure in Online Support Groups

(2021)

Millions of U.S. adults join online support groups to attain health goals, but the social ties they form are often too weak to provide the support they need. What impedes the strengthening of ties in such groups? We explore the role of demographic differences in causing the impediment and demographic self-disclosure in removing it. Using a field study of online quit-smoking groups complemented by three laboratory experiments, we find that members tend to hide demographic differences, concerned about poor social integration that will weaken their ties. However, the self-disclosures of demographic differences that naturally occur during group member discussions actually strengthen their ties, which in turn facilitates attainment of members’ health goals. In other words, social ties in online groups are weak not because members are demographically different, but because they are reluctant to self-disclose their differences. If they do self-disclose, this breeds interpersonal connection, trumping any demographic differences among them. Data from both laboratory and field about two types of demographic difference—dyad-level dissimilarity and group-level minority status—provide convergent support for our findings.

Cover page of Analysis of COVID-19 Patients With Acute Respiratory Distress Syndrome Managed With Extracorporeal Membrane Oxygenation at US Academic Centers.

Analysis of COVID-19 Patients With Acute Respiratory Distress Syndrome Managed With Extracorporeal Membrane Oxygenation at US Academic Centers.

(2021)

Objective

This study analyzed the outcomes of COVID-19 patients with ARDS who were managed with extracorporeal membrane oxygenation (ECMO) across 155 US academic centers.

Summary background data

ECMO has been utilized in COVID-19 patients with acute respiratory distress syndrome (ARDS) and refractory hypoxemia. Early case series with the use of ECMO in these patients reported high mortality exceeding 90%.

Methods

Using ICD-10 codes, data of patients with COVID-19 with ARDS, managed with ECMO between April and September 2020, were analyzed using the Vizient clinical database. Outcomes measured included in-hospital mortality, hospital and ICU length of stay, and direct cost. For comparative purposes, the outcome of a subset of COVID-19 patients aged between 18 and 64 years and managed with versus without ECMO were examined.

Results

1,182 patients with COVID-19 and ARDS received ECMO. In-hospital mortality was 45.9%, mean length of stay was 36.8 ± 24.9 days, and mean ICU stay was 29.1 ± 17.3 days. In-hospital mortality according to age group was 25.2% for 1 to 30 years; 42.2% for 31 to 50 years; 53.2% for 51 to 64 years; and 73.7% for ≥65 years. A subset analysis of COVID-19 patients, aged 18 to 64 years with ARDS requiring mechanical ventilation and managed with (n = 1113) vs without (n = 16,343) ECMO, showed relatively high in-hospital mortality for both groups (44.6% with ECMO vs 37.9% without ECMO).

Conclusions

In this large US study of patients with COVID-19 and ARDS managed with ECMO, the in-hospital mortality is high but much lower than initial reports. Future research is needed to evaluate which patients with COVID-19 and ARDS would benefit from ECMO.