Ramayya Krishnan

Dean of Heinz College
H. John Heinz III Dean and W. W. Cooper and Ruth F. Cooper Professor of Management Science and Information Systems
Heinz College, Carnegie Mellon University

February 18, 2011

Speakman Hall 200, 1000am – 1130am

Krishnan will present two papers related to social media . In addition, he will discuss the open problem of how one should think about privacy protection of network data using a decision-theoretic approach of trading off data utility with disclosure risk

Title 1: Dynamics of Network Structure and Content in Social Media

Abstract 1

Organizations use social media to leverage knowledge contributions by individual employees, which also foster social interactions { activity in blogs, forums, wikis etc. is critical to ensuring a thriving online community. Prior studies have examined contributions to such media at the level of the individual, focusing on drivers of participation, whereas we investigate three different dimensions of dyadic interactions. Our setting is an online forum in an enterprise, where employees both exchange knowledge by query-response and interact socially.
Using a networks approach to query-response behavior, we characterize each interaction as a directed tie, and view the entire set of online forum interactions as a social network. We evaluate network constructs including Simmelian embeddedness and content of relationships (expressive or instrumental), to understand the mechanisms underlying online social interactions.
We find that content and embedded nature of the relationship strongly influence responses: Simmelian ties formed in an expressive setting have the highest positive impact on response propensity, i.e. both content and embeddedness are impactful and reinforce each other. Our results have implications for designing online social communities, specifically that practitioners ought to consider the benefits of purely social interactions through the forum that may serve to lubricate future instrumental interactions.

Title 2:  Homophily or Influence? An Empirical Analysis of Purchase within a Social Network

Abstract 2

Consumers that are close to one another in a social network are known to have similar behaviors. The focus of this study is the extent to which such observed similarity is driven by homophily or social influence. Homophily refers to the similarity in product preferences between individuals who are connected. Social influence is the dependence of consumers’ purchase decisions on their communication with others. We construct a hierarchical Bayesian model to study both the timing and choice of consumer purchases within a social network. Our model is estimated using a unique social network dataset obtained from a large Indian telecom operator for the purchase of caller ringer-back tones. We find strong social influence effects in both the purchase-timing and product-choice decisions of consumers. In the purchase-timing decision, we find that consumers are three times more likely to be influenced by network neighbors than by other people. In the product-choice decision we find a strong homophily effect. We show that ignoring either homophily or social influence will result in overestimated effects of the other factor. Furthermore, we show that detailed communication data is crucial for measuring influence effect, and influence effect can be either over- or underestimated when such data is not available. Finally, we conduct policy simulations on a variety of target marketing schemes to show that promotions targeted using network information is superior. For example, we find a 4-21% improvement on purchase probability, and an 11-35% improvement for promoting a specific product.

For a copy of the paper1, click here.

For a copy of the paper2, click here.