Essays in Online Advertising

The last several years have seen a dramatic increase in the amount of time and money consumers spend online. As a consequence, the Internet has become an important channel that firms can use to reach out and connect to consumers which has lead to the emergence of online advertising.Given the scale and novelty of online advertising, there is a growing need to understand how consumers respond to online ads and how firms should advertise using this medium. In my dissertation, I study different aspects of sponsored search and display ads which constitute the bulk of online advertising. In the first essay, I focus on the issues related to the use of aggregate data in sponsored search. I demonstrate that models commonly used in sponsored search research suffer from aggregation bias and present the implications of this aggregation bias. In the second essay, I focus on the advertiser\u27s problem of bidding optimally in sponsored search auctions. In the third essay, I study the interactions between various forms of online advertising like banner ads, display ads and sponsored search ads and address the problem of attribution

When the Bank Comes to You: Branch Network and Customer Multi-Channel Banking Behavior

Customers today increasingly interact with their banks using digital channels, lifting the necessity for banks to rethink the distribution of physical branches and customer behavior in a multi-channel environment. Using approximately 1.2M anonymized individual-level data from a large commercial bank in US over 6 years, our paper investigates the traditional channel – bank branches – and the impact of its network change (branch opening or closure) on customer multi-channel preferences and other banking behavior. Our results show that both branch opening and closure are associated with decreasing transactions through offline channels and increasing transactions in online banking. Hence, branch network change is likely to result in customer migrating from offline channels to online banking. In addition, we find that opening branch is associated with customers’ adoption of additional banking products in a short term. Interestingly, closing a branch does not lead to more account closures by customers

The Influence Of Mobile Channel On Customer Behavior In Omni-Channel Banking Services

As mobile phones and tablets are in widespread use, the emergence of mobile channel is changing the way customers interact with financial institutions. In this research, we empirically examine how the use of mobile devices can improve customer informedness and affect customer behavior in financial transactions. We use a large-scale customer transaction data obtained from one of the largest commercial banks in the United States. Specifically, we investigate: (1) whether the use of mobile phones and tablets is associated with a higher level of customer informedness and demand for services; and (2) compared to customers that only transact through a PC, whether mobile phone and tablet users are less likely to incur overdraft and credit card penalty fees. This paper contributes new knowledge in omni-channel banking services by examining post-adoption customer behavioral changes using transaction-level observations. We also discuss insights for banks’ managers related to the design of new mobile channel, and strategic management of existing digital and physical channels

Agency Selling or Reselling? Channel Structures in Electronic Retailing

In recent years, online retailers (also called e-tailers) have started allowing manufacturers direct access to their customers while charging a fee for providing this access, a format commonly referred to as agency selling. In this paper, we use a stylized theoretical model to answer a key question that e-tailers are facing: When should they use an agency selling format instead of using the more conventional reselling format? We find that agency selling is more efficient than reselling and leads to lower retail prices; however, the e-tailers end up giving control over retail prices to the manufacturer. Therefore, the reaction by the manufacturer, who makes electronic channel pricing decisions based on their impact on demand in the traditional channel (brick-and-mortar retailing), is an important factor for e-tailers to consider. We find that when sales in the electronic channel lead to a negative effect on demand in the traditional channel, e-tailers prefer agency selling, whereas when sales in the electronic channel lead to substantial stimulation of demand in the traditional channel, e-tailers prefer reselling. This preference is mediated by competition between e-tailers—as competition between them increases, e-tailers prefer to use agency selling. We also find that when e-tailers benefit from positive externalities from the sales of the focal product (such as additional profits from sales of associated products), retail prices may be lower under reselling than under agency selling, and the e-tailers prefer reselling under some conditions for which they would prefer agency selling without the positive externalities

Aggregation Bias in Sponsored Search Data: The Curse and the Cure

Recently there has been significant interest in studying consumer behavior in sponsored search advertising (SSA). Researchers have typically used daily data from search engines containing measures such as average bid, average ad position, total impressions, clicks, and cost for each keyword in the advertiser’s campaign. A variety of random utility models have been estimated using such data and the results have helped researchers explore the factors that drive consumer click and conversion propensities. However, virtually every analysis of this kind has ignored the intraday variation in ad position. We show that estimating random utility models on aggregated (daily) data without accounting for this variation will lead to systematically biased estimates. Specifically, the impact of ad position on click-through rate (CTR) is attenuated and the predicted CTR is higher than the actual CTR. We analytically demonstrate the existence of the bias and show the effect of the bias on the equilibrium of the SSA auction. Using a large data set from a major search engine, we measure the magnitude of bias and quantify the losses suffered by the search engine and an advertiser using aggregate data. The search engine revenue loss can be as high as 11% due to aggregation bias. We also present a few data summarization techniques that can be used by search engines to reduce or eliminate the bias

Does journaling encourage healthier choices? Analyzing healthy eating behaviors of food journalers

Best paper award at DH 2018</p

A rapid method for measuring olfactory responses of Drosophila larva

This article does not have an abstract

Eat & tell: A randomized trial of random-loss incentive to increase dietary self-tracking compliance

National Research Foundation (NRF) Singapore under International Research Centres in Singapore Funding Initiativ