UMD Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/3

New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a given thesis/dissertation in DRUM.

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SOCIAL NETWORK INFLUENCE ON INFANT FEEDING DECISIONS AMONG LATINX WOMEN
(2023) Channell Doig, Amara J; Aparicio, Elizabeth M; Public and Community Health; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Nutrition during the first 1000 days of life is critical for lifelong physical and mental health. Infant milk choices, introduction of complementary foods, and responsive feeding methods can contribute to risk for infection, chronic disease, mental health, and later nutrition and dietary practices. Current feeding interventions are likely to focus on the mother’s decision-making and frequently neglect to explore the impact of the people around her. Little is known about how social networks can influence feeding decisions and how this may impact the acceptance of recommendations from health professionals or intervention content. This dissertation used a convergent mixed methods approach to explore how social networks influence infant feeding decisions and practices for Latinx women in the U.S. In the quantitative portion, 30 participants completed egocentric network mapping to explore network structure and tie strength. In the qualitative portion, 15 of the participants completed in-depth interviews to allow for a better understanding of the influence that network members have, as well as mothers’ decision-making processes. The quantitative and qualitative strands were integrated to allow for a deeper understanding of the social context in which feeding decisions are made. Three manuscripts are presented in the dissertation. The first explores infant feeding support networks and other social influences, including culture and maternal intuition. The participants tended to have small networks and different levels of cultural influence depending on immigration status. The second manuscript examined the influence of information about infant feeding from personal communication compared to online channels. Participants valued the information from medical providers or their support networks and although many used the internet, they had concerns about the information found there. The third manuscript looked at the experiences of the participants who were formula-feeding during the 2022 formula shortage. Although the participants fought to breastfeed their children, they needed to switch to formula to protect their physical and mental health and be there for them. The formula shortage added stress and took an emotional toll on the participants. The dissertation results confirm the importance of social networks as sources of information and support for Latinx mothers with infants during the first year of life. Overall, there was a need for additional support during this time and additional barriers to infant feeding for immigrant mothers. Direct practice implications include how interventions can be developed to provide support. Policy implications include the need to improve structural support for infant feeding, including access to lactation care and food. Future research should continue to assess network support and could look at sociodemographic differences.
Earnings Uncertainty and Nonprofessional Intermediaries
(2021) Hyman, Cody Alyssa; Seybert, Nick; Business and Management: Accounting & Information Assurance; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Prior research is mixed on individual investors’ ability to utilize earnings information and generally credits professional information intermediaries with alleviating processing costs. Over the past decade, individual investors increasingly rely on online social networks to help them process the information they use to trade. This paper investigates the role of earnings uncertainty (persistence, predictability, smoothness, and accrual quality) as a processing cost and the ability of nonprofessional intermediaries to ameliorate this cost. Using comments and trades made on a popular social trading platform as raw and applied information, respectively, I show that raw information is impeded by earnings uncertainty while applied information reduces integration costs to improve the use of earnings information.
INFORMATION TRANSPARENCY AND USER BEHAVIOR IN EMERGING ONLINE MARKETPLACES: EMPIRICAL STUDIES OF SOCIAL MEDIA AND OPEN INNOVATION MARKETS
(2013) AL-HASAN, ABRAR; Viswanathan, Siva; Lucas, Hank; Business and Management: Decision & Information Technologies; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Web 2.0 and social media have significantly increased the amount of information available to users not only about firms and their offerings, but also about the activities of other individuals in their networks and markets. It is widely acknowledged that this increased availability of information is likely to influence a user's behavior and choices. However, there are very few systematic studies of how such increased information transparency influences user behavior in emerging marketplaces. My dissertation seeks to examine the impact of increased information transparency - particularly, information about other individuals - in two emerging platforms. The first essay in my dissertation compares online "social" marketing on Facebook with "non-social" marketing and examines their relative impacts on the likelihood of adoption, usage and diffusion of an "App". While social marketing - wherein a user gets to see which of her other friends have also "liked" the product being marketed- is one of the fastest growing online marketing formats, there are hardly any studies that have examined the value of the social aspect of such marketing. I find that social marketing is associated with increased app adoption, usage, and diffusion as compared to non-social marketing. The study also uncovers interesting tradeoffs between the effects of different types of "social" information on user behavior outcomes. The second essay examines the behavior of contestants in an open innovation design marketplace, wherein firms seek solutions from a crowd through an online contest. The study examines how the availability of information about other contestants as well as the availability of feedback information provided to others by the contest holder, impacts a focal contestant's behavior and outcomes. I find that contestants adopt different strategic behaviors that increase their odds of winning the contest under the different information-transparency regimes. The findings have interesting implications for the design of online contests and crowdsourcing markets. Overall, my dissertation provides a deeper understanding of how the visibility of different types of information in online platforms impacts individual behaviors and outcomes.
ONLINE NETWORKS AND PROSOCIAL BEHAVIORS: EMPIRICAL STUDIES OF CHARITABLE DONATIONS AND ENVIRONMENTAL SUSTAINABILITY
(2013) Yim, Dobin; Viswanathan, Siva; Lucas, Hank C; Business and Management: Decision & Information Technologies; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
My dissertation seeks to understand how online networks promote prosocial behaviors in creating social value. The first essay examines the use of Twitter on charitable giving behavior in online fundraising campaigns. Using a unique dataset from one of the first nonprofit organizations to conduct an online fundraising campaign via Twitter, the goal of this essay is to understand how social media and the interpersonal communications it facilitates influences donation outcomes. I find that generic content sent through a mass broadcast mode has a negative influence, whereas personalized content sent through a narrowcast mode has a positive influence on a focal agent's donation behavior. I further show that different types of persuasive content have varied impacts on outcomes. In the interpersonal context, content related to maintaining social relationships such as the visibility of other members' donations, the diversity of sources advocating action, and strengthening interpersonal bonds, positively influence donation behavior, especially for those whose social ties with the charitable organization are weak. The second essay examines the design of online communities in supporting grassroots movements towards environmental sustainability. Using a dataset from one of the early pioneers of "green" online communities, the goal of this essay is to understand how online networks impact sustainable behaviors. Drawing from literature on observational learning and environmental sustainability, I show that a member's total carbon savings is mainly influenced by the exposure to relevant others' "green" behaviors. More specifically, a member's decision to commit and perform a sustainable act is determined by the organizational structure and strength of relationships with fellow members. While organizing members into groups decreases individual's environmental effectiveness in terms of total carbon savings, especially in larger groups, a higher frequency of communications among members increases sustainable behavior by enhancing interpersonal connections. Overall, the two studies provide important theoretical and practical implications for prosocial behaviors supported by online networks.
TRANSMIGRANCY EXPERIENCES OF EASTERN AND CENTRAL EUROPEAN AU PAIRS IN THE WASHINGTON D.C., METROPOLITAN AREA
(2013) Celik, Nihal; Korzeniewicz, Roberto P; Sociology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
This dissertation explores transmigrancy experiences of au pairs by examining the processes of building and maintaining transnational mobilities among this population. These processes involve these women's motivations for becoming au pairs in the United States, settlement plans and strategies prior and subsequent to migration, and long-term incorporation patterns in the home and host countries. I employ intersectionality and transnational feminist frameworks of analysis in order to contextualize and scrutinize multidimensionality of women's transmigrancy experiences at multiple levels. At the individual level, I look at the extent of transmigrant women's agency in seeking their initial and long-term settlement plans. At the intermediate level, I examine the extent of their social networks in shaping their settlement and incorporation goals by analyzing formation, types, and sustenance of these networks at the local and transnational levels. At the structural level, I investigate the structural contexts their agency is embedded in, and how their transmigrancy experiences and practices relate to structural power relations of gender, social class, marital status, nationality, and immigration status. The findings of this research draw on a three-year-long feminist ethnographic study of transmigrant women who originated from Eastern and Central European post-communist countries, entered the United States through au pair programs and were residing in the Washington, D.C., Metropolitan Area. I show that these women were primarily motivated to partake in au pair programs for non-economic goals such as cultural exchange, and planned short-term settlement. However, in the long-term, they sought to sustain double affiliation in their home countries and the United States for negotiating oppressive economic, cultural, and social structures intensified with post-communist transition in their home countries. In doing so, they managed to maintain a legal immigration status and ultimately planned to obtain permanent residency rights in the United States. The empirical findings of the dissertation challenge overgeneralized assumptions on transmigrants' agency, social networks, settlement, and incorporation patterns in transnationalism scholarships. It also contributes a nuanced understanding of the dynamics and complexities of building and maintaining transnational mobilities among an under-researched population; namely, au pair transmigrants.
Early Childhood Nutritional Responses to Targeted Food Aid and Social Network Disruptions in Ugandan Internally Displaced Person's Camps
(2009) Adelman, Sarah Wallace; Leonard, Kenneth L; Agricultural and Resource Economics; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Early childhood malnutrition, which is a series of symptoms including slow linear growth, decreased resistance to infection, and poor motor and cognitive functioning, has received increased attention in recent years as a key to economic development. While malnutrition can affect people at any age, the effects of malnutrition are most damaging in utero and during the first two years of life. Deficits during this period have long-term effects on health, educational attainment and productivity in adulthood. Thus, investing in efforts to provide children with minimal required nutrition can substantially improve future household welfare and promote economic development. In Northern Uganda, parents had limited control over their children's nutritional outcomes as nearly all rural households were living in internally displaced persons (IDP) camps due to a civil conflict. Food in these camps was scarce, sanitation conditions were poor, and health care was underprovided. Additionally, the displacement severely disrupted the strong social structures in place in the village that households relied on day to day for many activities, including care for children. This dissertation looks at early childhood health outcomes in these IDP camps and how these outcomes are affected by a food aid program and by social network influences. Chapter 3 examines the spillover effects of two types of food for education (FFE) programs on the nutritional outcomes of eligibles' younger siblings. FFE programs are criticized on the grounds that household redistribution responses mitigate nutritional benefits from the programs. However, this study shows that in some cases households redistribute program benefits to younger children who can benefit more from marginal improvements in nutritional status, which could increase returns to FFE. In Chapter 4, I look at the effects of local social networks, the friends and family that households interact with on a daily basis, on preschoolers' nutritional outcomes. Social networks can affect demand for human capital investments by relaxing household time or budget constraints or by defining and reinforcing human capital preferences. However, empirically identifying the effect of social networks on human capital investment is usually problematic because households self-select their networks in ways that may be correlated with their abilities to make these investments. In Northern Ugandan Internally Displaced Persons Camps, networks were not entirely self-selected. Rebel activity, which forced households into camps in 2002, disrupted pre-existing social networks in ways that were exogenous to household human capital preferences. This paper uses the exogenous variation in network disruption to identify the impact of networks on child health outcomes. Using household survey data from the Uganda School-Based Feeding Evaluation, household data that I collected, and administrative data from the World Food Programme and local governments, I show that an increase in the average household's network size by one household (or roughly 25 percent of the network) improves height-for-age z-scores by .25 standard deviations for children born in the camp. This improvement is equivalent to moving from the 8th percentile to the 13th percentile in height for the average child in this sample. The result stands up to numerous falsification tests. Additionally, I find no evidence that in-camp network strength impacts nutritional outcomes determined before displacement, supporting the exogeneity of the disruption to household health preferences.
Modeling the Dynamics of Opinion Formation and Propagation: An Application to Market Adoption of Transportation Services
(2007-08-29) Kozuki, Aaron T.C.Y.; Mahmassani, Hani S.; Civil Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
The objective of this research is to present a model that utilizes social and learning mechanisms to first explore the underlying dynamics of opinion formation and propagation, and then applies those mechanisms to an application of freight mode choice to investigate the effect that opinions have on choice set considerations, attribute perceptions, and the market adoption of a new rail freight service. Primary contributions of this research include the explicit modeling of social and learning mechanisms and their effects on opinion formation and propagation, the evolution of these opinions over time, and an exploration of the role that opinion dynamics have in choice processes. Research findings will offer insight to the process of evolving attitudes, perceptions, and opinions and the effects on individuals' judgment and decision making. It will also offer insight to the effects of attribute distortion on decision making.
Formalizing the Informal: A Network Analysis of an Insurgency
(2006-06-27) Reed, Brian; Segal, David R.; Sociology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
This research project applies Social Network Analysis to Saddam Hussein's network and demonstrates how network analysis techniques uncovered a web of family and tribal linkages that resulted in the ousted dictator's capture. I use Simmel's approach to affiliations and interactions among consensual actors as the frame in which to view why and how warfare operates the way it does in the present context of an insurgency, and what difference it makes for states (and non-states) that war is waged in this particular manner. This project adds to the emerging sociology of war that is not primarily concerned with why wars start or why some states wage war against others, but rather with how wars work once opponents are engaged. I used two mapping networks and six associated sub-networks - trust (immediate family, extended family, close friendships, bodyguards) and strategy and goals (money and resources, insurgent operations) - to identify the structural and relational characteristics of the network. Network concepts allowed me to highlight the structure of the previously unobserved associations by focusing on the pre-existing relationships and ties that bind together such a group. By focusing on the roles, organizational positions, and those actors who are prominent and/or influential, I was able to get a sense of how the associations were structured and how the group functioned, how members were influenced and power was exerted, and how resources were exchanged. I found that insurgent members co-opted pre-existing ties to facilitate their operations. Roles are defined according to these pre-existing ties - primarily familial ties, but also those linked by previous political, tribal, or organizational association. Key individuals are connected to one another, thus forming a domain for each that gives them a high status in terms of prestige and influence. Those that are not part of this core group and who sit on the periphery of these critical task relationships extend the network and allow it to operate at a far greater distance. In short, social network analysis allowed me to formalize the informality of the insurgent network by visualizing the structure of one that we did not readily observe.
The Influence of Career Identity and Social Networks on Career Transition Magnitude
(2006-06-01) Slay, Holly Selena; Taylor, Susan; Management and Organization; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Increasingly, scholars and journalists are suggesting that there is a trend toward greater magnitude in career transitions signified by the crossing of career boundaries (such as level, functional, organizational, industry and professional boundaries). To date, much of the quantitative empirical research suggests that organizational, relational and environmental factors influence career transition behavior. However, while we know that these external influences may cause an individual to transition, we know less about the process through which career transitions evolve, especially those of larger magnitude and how forces internal to the individual may help to explain variance above and beyond these external factors. In this dissertation, I use qualitative and quantitative methodologies to develop and refine a model of career transition focusing on career transition magnitude. Specifically, I use research from social identity, social networks and role exit theory to develop a model of career transition magnitude that posits career identity (the cognitive representation of the self derived from past career experiences, beliefs, values, attributes and motives that define the individual in terms of their career) and network characteristics (the pattern of interpersonal relationships) influence the magnitude of intended career transition, the career exit behaviors one engages in and the evaluation of career opportunities. Further, I use path analysis to find that career exit behaviors are influenced by the magnitude of the intended career transition as well as strong coworker ties and social and personal turbulence. Additionally, I find that the favorable evaluation of career transition opportunities is impacted by career identity centrality and organizational satisfaction. Finally, I find that the magnitude of the intended career transition is influenced by the favorable evaluation of transition opportunities, network career range, organizational satisfaction and social and personal turbulence. Theoretical and practical contributions are discussed.
Computing and Applying Trust in Web-based Social Networks
(2005-04-11) Golbeck, Jennifer Ann; Hendler, James; Computer Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
The proliferation of web-based social networks has lead to new innovations in social networking, particularly by allowing users to describe their relationships beyond a basic connection. In this dissertation, I look specifically at trust in web-based social networks, how it can be computed, and how it can be used in applications. I begin with a definition of trust and a description of several properties that affect how it is used in algorithms. This is complemented by a survey of web-based social networks to gain an understanding of their scope, the types of relationship information available, and the current state of trust. The computational problem of trust is to determine how much one person in the network should trust another person to whom they are not connected. I present two sets of algorithms for calculating these trust inferences: one for networks with binary trust ratings, and one for continuous ratings. For each rating scheme, the algorithms are built upon the defined notions of trust. Each is then analyzed theoretically and with respect to simulated and actual trust networks to determine how accurately they calculate the opinions of people in the system. I show that in both rating schemes the algorithms presented can be expected to be quite accurate. These calculations are then put to use in two applications. FilmTrust is a website that combines trust, social networks, and movie ratings and reviews. Trust is used to personalize the website for each user, displaying recommended movie ratings, and ordering reviews by relevance. I show that, in the case where the user's opinion is divergent from the average, the trust-based recommended ratings are more accurate than several other common collaborative filtering techniques. The second application is TrustMail, an email client that uses the trust rating of each sender as a score for the message. Users can then sort messages according to their trust value. I conclude with a description of other applications where trust inferences can be used, and how the lessons from this dissertation can be applied to infer information about relationships in other complex systems.

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