İşletme Lisansüstü Programı - Doktora

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  • Öge
    Gıda Tercihi ve Tüketiminde Sağlık İlişkili Tutarlılık: Hane Halkı ve Ürün Özelliklerinin Rolü
    ( 2020) Sürmeli, Gökhan ; Kemal Burç Ülengin ; 623222 ; İşletme Mühendisliği ; Management Engineering
    The prevalence of overweight and obesity around the world has reached alarming levels in the last decades. The adverse effects of overweight and obesity on human health are well documented. Individuals with excess body weight carry a higher risk of fatal health issues such as type-2 diabetes, cardiovascular diseases, and cancer. In addition, overweight and obesity have negative psychosocial, and economic consequences. Inevitably, counteracting obesity and reducing the associated health costs have become major policy goals for many countries including Turkey. Food consumption behaviors are known to be one of the main causes of the obesity epidemic. In order to maintain a normal weight and avoid diet-related diseases, consumers are expected to follow a range of dietary recommendations consistently over time and across different consumption situations. In practice, however, consumers display desirable behaviors in some of their consumption decisions whereas they fail in others. It is essential to understand the situations under which consumers engage in (in)consistent consumption behaviors in order to develop better public health strategies. Despite the prevalence of obesity and diet-related diseases, little is known about the dynamic associations between food purchasing behaviors in the grocery retailing environment. This thesis focuses on different aspects of healthy food purchasing behaviors from a consistency perspective. Using a large household panel data from Turkey, three econometric studies are conducted within the scope of the thesis. One of the aims of this thesis is to explore how grocery shopping behaviors and sociodemographic characteristics are associated with healthy and unhealthy food purchasing patterns. In the first empirical study within the scope of this thesis (Study-1), the effects of shopping behaviors including shopping frequency, basket size, preference for promotions, choice of store type as well as sociodemographic characteristics of households on the share of food expenditures for the categories that are recommended to be avoided (foods with high sugar) and to be approached (fruits, vegetables, and legumes) are analyzed using linear mixed effects models. The results of Study-1 demonstrates that both shopping behaviors and sociodemographic characateristics are associated with the healthiness of food purchases. However, the drivers of avoiding sugary foods are not identical to the drivers of approaching healthy foods. Preference of modern retailer formats, making less promotional purchases, smaller number of shopping trips, smaller number of purchases, higher level of education is found to improve purchasing patterns both in terms of avoiding sugary foods and approaching fruits, vegetables, and legumes. Meanwhile, some of the sociodemographic characteristics such as higher level of income, being in later stages of life, and living in more urbanized neighborhoods is found to reduce the share of sugary foods but do not improve the purchasing patterns in terms of the share of healthy categories in Turkey. In response to the growing interest in healthy eating, nutrition claims on food products such as "diet", "low-fat", "source of fibre" have become a popular marketing tool among food companies to emphasize the nutritional benefits of their products. Previous studies have shown that choosing food with nutrition claims can lead to overconsumption or license subsequent unhealthy choices. However, research focusing on systematic cross-category effects in real-life settings is missing. To address this gap, the second empirical study in this thesis (Study-2) aims to explore how the choice of food with nutrition claims is associated with the healthiness of the entire shopping basket by estimating fixed effects panel models. The results of Study-2 show that choosing a higher share of items with nutrition claims within hedonic categories leads to healthier shopping baskets (consistent behavior). This finding suggests that a self-control mechanism remains active due to the high goal conflict between health and pleasure. One the other hand, choosing a higher share of items with nutrition claims within utilitarian categories leads to less healthy shopping baskets (inconsistent behavior or balancing). This spillover can be explained by a perceived goal progress and lower perceived goal conflict between short term pleasure and long-term health for utilitarian products with nutrition claims. Another important marketing activity which has harmed consumers' dietary patterns is the pricing strategy. Calorie-dense, unhealthy foods have not only become cheaper over the years but also have been more heavily promoted in the marketplace. In recent years, it has been widely discussed that consumers can be nudged towards healthier food consumption patterns through price-based policies. In order to predict the effectiveness of price-based interventions, there is a need to conduct research on price sensitivities of consumers for healthy and unhealthy food. Despite the vast amount of literature comparing price elasticity of demand for aggregate food categories, only a limited number of studies have addressed the interaction of price and nutrition claims in terms of its effect on demand response patterns. Finally, this thesis investigates whether and to what extent the price sensitivity of households in terms of their purchase quantity responses change when they choose relatively healthy items with nutrition claims. In the last empirical study within the thesis (Study-3), transaction level demand responses are compared for the purchases of items with and without nutrition claims in different food categories by estimating random effects panel models. The relative impact of price increases and price decreases with respect to the internal reference price are compared both for regular items and items with nutrition claims in multiple categories. Besides, the impact of the intensity of choosing items with nutrition claims within and across categories (which is used as a measure of adopting nutrition claims) on the price sensitivity is analyzed. The findings of Study-3 show that consumers are generally less price sensitive for items with nutrition claims in terms of their purchase quantity responses compared to regular items in the same category. Purchase quantity responses are generally found to be asymmetric both for regular items and items with nutrition claims. For regular items, price sensitivity is relatively higher when there is a decrease in price. For items with nutrition claims, asymmetry in demand responses to the direction of the price change depends on the food category. A higher adoption of items with nutrition claims within a category in past purchases is found to decrease the price sensitivity for these items. On the other hand, choosing items with nutrition claims in an increasing number of categories reduces the price sensitivity for regular items but does not tend to influence the price sensitivity for items with nutrition claims. This thesis contributes to the public health and consumer behavior literature with several valuable insights, which have implications both for policymakers and marketers. Commercial purchase data are continuously collected for market research companies and contains detailed marketing mix and demographic information regarding real-world purchasing transactions. These types of datasets allow researchers to observe the short and long-term impact of marketing and policy interventions on actual food purchases, which in turn indicates the changes in dietary patterns. This thesis is also unique in terms of using commercial purchase data from Turkey for health-related consumer research.
  • Öge
    Reconciling History And Theory: The Narrative Of Institutional Change And Discourse In And Around The Turkish Cooperative Forms, 1861-1980
    (Institute of Social Sciences, 2020) Soydemir, Cemil Ozan ; Erçek, Mehmet ; 630401 ; Management ; İşletme
    The reconciliation of history and theory in organization studies has become a vibrant research topic for almost two decades. Although history had already constituted an integral part of theoretical research long before this growing interest, recent calls have urged a keener approach toward history-theory rapprochement by not prioritizing one over the other. In a similar vein, the expedient studies have increasingly taken place in the research domain of institutional change that explores the mechanisms, actors, and logics that trigger, initiate, maintain, and/or resist such changes in institutional fields and organizational forms. What is more, the last decade has witnessed an upsurge in business history research that explores cooperatives as unique organizational forms in terms of their distinctive normative ground and particular practices, which embody in tandem cooperative's archetypal configuration. However, historically informed theoretical studies on institutional change of cooperative forms are rare and have become mostly intensified around the Western cooperative models. When it comes to the Turkish setting, there has been no such a scholarly interest in nor theoretical studies about the historical trajectory experienced by the Turkish cooperative forms.
  • Öge
    Crowdfunding Community Engagement: Drivers And Outcomes
    (Institute of Social Sciences, 2019) Demiray, Melek ; Burnaz, Şebnem ; 584898 ; Management ; İşletme
    Sharing economy and co-creative networks have changed the way of interaction and cooperation in the businesses of digital age. The concepts of 'co-creation', 'co-funding' and 'peer-to-peer' become inevitable parts of sustainable innovation, crowd economy, and entrepreneurship. Crowdfunding, as a novel financial system, has emerged to facilitate accessing funds, enable crowd economy, encourage innovation and democratize the entrepreneurship ecosystem. Crowdfunding is basically gathering a small amount of money from a large number of people, namely the 'crowd' in a community or in a society to realize a specific project. Crowdfunding market has rapidly spread around the world in recent years since crowdfunding offers an alternative financing method to fulfill the gaps in the financial sector and to enable individuals, start-ups and SME's to cope with capital access problem in a feasible manner. The crowdfunding platforms bring members together to raise capital and provide required information about projects through online settings. Crowdfunding platforms are considered as online communities since they establish closer relationships among their users to share resources for co-creating value.
  • Öge
    Analyzing Customer Engagement Through Customer Experience In Health Care Industry
    (Institute of Social Sciences, 2019) Özçelik, Ayşe Bengi ; Burnaz, Şebnem ; 554264 ; Management ; İşletme
    The unilateral relationship between brand and consumer in 1980s has become a unilateral and interactive one in which consumer is empowered. This transformation increased the competition in market and changed the approach of organizations about their clients, accordingly the importance of consumer-brand interaction is increased. In 2000s, a paradigm shift is actualized in marketing in which the service become the focus. With this shift, it is widely accepted that the critical identity of a brand is built by the service provided even if the brand is a manufacturing one. Technological developments supported this transformation by putting the information flow forward and help consumers being empowered. Hence, experience has become the new focus of marketing by converting the traditional exchange relationship. Organizations should provide a well-designed experience story in order to sustain their existence in the market.
  • Öge
    Investor Attention And Social Media Sentiment In International Stock Returns And Trading Activity
    (Institute of Social Sciences, 2019) Tan, Selin Düz ; Taş, Oktay ; 600613 ; Management ; İşletme
    Yatırımcıların bilgi işleme konusunda zaman, çaba ve bilişsel kaynakları kısıtlıdır. Etkin piyasa hipotezine dayanan geleneksel sermaye varlık fiyatlandırma modeli, menkul kıymetler hakkındaki bilgilerin anında fiyatlara yansıdığını varsaymaktadır. Bu durum gerçek hayatta her zaman doğru değildir ve yatırımcılar sınırlı bilgiye sahip olabilir. Son yıllarda gelişme gösteren sosyal medya platformları araştırmacıların yatırımcıların karmaşık davranışlarını keşfetmelerini sağlamaktadır. Bu tezin asıl amacı, Google arama hacmi endeksi ile ölçülen yatırımcı ilgisinin, tweet sayısı ile ölçülen sosyal medya faaliyeti ve Twitter yatırımcı duyarlılığı ile ölçülen sosyal medya duyarlılığının hisse senedi getirileri ve işlem hacmi üzerindeki etkilerini araştırmaktır. Tezde beklenen getiri ile faktör katsayıları arasındaki ilişkiyi araştırmak için finans literatüründe yaygın olarak kullanılan Fama ve MacBeth regresyon modeli kullanılmaktadır. Tezde Google arama hacmi endeksi iki temel nedene dayanarak yatırımcı ilgisinin ölçütü olarak kullanılmaktadır. Birincisi, bireyler genellikle bilgi toplamak için internet arama motorunu kullanmakta olup bu durum Google arama hacminin toplam hane halkının ilgisini temsil edebileceğini göstermektedir. İkincisi, Google arama hacmi endeksi verileri, yatırımcıların davranış veya kararlarını, işlem hacmi, haber sayısı ve normal üstü getiriler gibi diğer yatırımcı ilgisi ölçütlerine göre daha iyi yansıtmaktadır; çünkü internet arama hacmi, yatırımcı ilgisinin diğer değişkenler gibi pasif olmayan alım faaliyetleri ile ilgili doğrudan bir ölçütüdür.