Sinan Aral

MIT · MIT Sloan School of Management

How do firms benefit from integrated enterprise systems (IES), and how does the IES implementation strategy influence the returns from IES? We investigated the implementation strategy that firms should follow to integrate multiple enterprise systems regarding the timing of adoption and the richness of modules. Borrowing theories from software devel...

Online marketplace designers frequently run randomized experiments to measure the impact of proposed product changes. However, given that marketplaces are inherently connected, total average treatment effect (TATE) estimates obtained through individual-level randomized experiments may be biased because of violations of the stable unit treatment val...

Decision makers often want to target interventions so as to maximize an outcome that is observed only in the long term. This typically requires delaying decisions until the outcome is observed or relying on simple short-term proxies for the long-term outcome. Here, we build on the statistical surrogacy and policy learning literatures to impute the...

Despite the availability of multiple safe vaccines, vaccine hesitancy may present a challenge to successful control of the COVID-19 pandemic. As with many human behaviors, people’s vaccine acceptance may be affected by their beliefs about whether others will accept a vaccine (i.e., descriptive norms). However, information about these descriptive no...

Identity cues appear ubiquitously alongside content in social media today. Some also suggest universal identification, with names and other cues, as a useful deterrent to harmful behaviours online. Unfortunately, we know little about the effects of identity cues on opinions and online behaviours. Here we used a large-scale longitudinal field experi...

The authors analyzed data from multiple large-scale randomized experiments on LinkedIn’s People You May Know algorithm, which recommends new connections to LinkedIn members, to test the extent to which weak ties increased job mobility in the world’s largest professional social network. The experiments randomly varied the prevalence of weak ties in...

The strength of weak ties and brokerage theory both rely on the argument that weak bridging ties deliver novel information to create “vision advantages” for actors in brokerage positions. However, our conceptualization of novelty is itself fundamentally underdeveloped. We, therefore, develop a theory of how three distinct types of novelty—diversity...

We propose an interpretable model that combines the simplicity of matrix factorization with the flexibility of neural networks to model evolving user interests by efficiently extracting nonlinear patterns from massive text data collections.

In an interconnected world, understanding policy spillovers is essential. We propose a program evaluation framework to measure policy spillover effects and apply that framework to study the governmental responses to COVID-19 in the United States. Our analysis suggests the presence of social spillovers. We estimate that while state closures directly...

Policy and communication responses to COVID-19 can benefit from better understanding of people's baseline and resulting beliefs, behaviors, and norms. From July 2020 to March 2021, we fielded a global survey on these topics in 67 countries yielding over 2.0 million responses. This paper provides an overview of the motivation behind the survey desig...

In recent years, there has been significant interest in understanding users' online content consumption patterns. But, the unstructured, high-dimensional, and dynamic nature of such data makes extracting valuable insights challenging. Here we propose a model that combines the simplicity of matrix factorization with the flexibility of neural network...

Despite the availability of multiple safe vaccines, vaccine hesitancy may present a challenge to successful control of the COVID-19 pandemic. As with many human behaviors, people's vaccine acceptance may be affected by their beliefs about whether others will accept a vaccine (i.e., descriptive norms). However, information about these descriptive no...

Most of the empirical evidence on social advertising effectiveness focuses on a single product at a time. As a result, little is known about how the effectiveness of social advertising varies across product categories or product characteristics. We therefore collaborated with a large online social network to conduct a randomized field experiment me...

Decision-makers often want to target interventions (e.g., marketing campaigns) so as to maximize an outcome that is observed only in the long-term. This typically requires delaying decisions until the outcome is observed or relying on simple short-term proxies for the long-term outcome. Here we build on the statistical surrogacy and off-policy lear...

Data sharing, research ethics, and incentives must improve

Most online content publishers have moved to subscription-based business models regulated by digital paywalls. But the managerial implications of such freemium content offerings are not well understood. We, therefore, utilized microlevel user activity data from the New York Times to conduct a large-scale study of the implications of digital paywall...

Significance As local governments relax shelter-in-place orders worldwide, policy makers lack evidence on how policies in one region affect mobility and social distancing in other regions and the consequences of uncoordinated regional policies adopted in the presence of such spillovers. Our analysis suggests the contact patterns of people in one re...

Social distancing is the core policy response to COVID-19. But as federal, state and local governments begin opening businesses and relaxing shelter-in-place orders worldwide, we lack quantitative evidence on how policies in one region affect mobility and social distancing in other regions and the consequences of uncoordinated regional policies ado...

Online marketplace designers frequently run A/B tests to measure the impact of proposed product changes. However, given that marketplaces are inherently connected, total average treatment effect estimates obtained through Bernoulli randomized experiments are often biased due to violations of the stable unit treatment value assumption. This can be p...

In an A/B test, the typical objective is to measure the total average treatment effect (TATE), which measures the difference between the average outcome if all users were treated and the average outcome if all users were untreated. However, a simple difference-in-means estimator will give a biased estimate of the TATE when outcomes of control units...

It remains unknown whether personalized recommendations increase or decrease the diversity of content people consume. We present results from a randomized field experiment on Spotify testing the effect of personalized recommendations on consumption diversity. In the experiment, both control and treatment users were given podcast recommendations, wi...

Bundling, the practice of jointly selling two or more products at a discount, is a widely used strategy in industry and a well examined concept in academia. Historically, the focus has been on theoretical studies in the context of monopolistic firms and assumed product relationships, e.g., complementarity in usage. We develop a new machine-learning...

Rigorous causal analysis could help harden democracy against future attacks

In the version of this Letter originally published, in the key for Fig. 1 the red square was mistakenly labelled ‘Low influence’ and ‘High susceptibility’ but should have been labelled ‘High influence’ and ‘Low susceptibility’. This has now been corrected.

Social influence maximization models aim to identify the smallest number of influential individuals (seed nodes) that can maximize the diffusion of information or behaviours through a social network. However, while empirical experimental evidence has shown that network assortativity and the joint distribution of influence and susceptibility are imp...

Lies spread faster than the truth There is worldwide concern over false news and the possibility that it can influence political, economic, and social well-being. To understand how false news spreads, Vosoughi et al. used a data set of rumor cascades on Twitter from 2006 to 2017. About 126,000 rumors were spread by ∼3 million people. False news rea...

We leveraged exogenous variation in weather patterns across geographies to identify social contagion in exercise behaviours across a global social network. We estimated these contagion effects by combining daily global weather data, which creates exogenous variation in running among friends, with data on the network ties and daily exercise patterns...

Supplementary Figures, Supplementary Tables, Supplementary Notes and Supplementary References

The GPS recorded running footprint of Manhattan during a sunny Saturday afternoon.

The GPS recorded running footprint of Manhattan during a rainy Saturday afternoon.

Many theories address how information technology (IT) affects the number of suppliers and supply chain governance. However, their predictions are at times contradictory and there is relatively little empirical evidence with which to evaluate them. We therefore develop an integrated, multiperiod model of the optimal number of suppliers that combines...

“The Strength of Weak Ties” (Granovetter 1973) arguably contains the most influential sociological theory of networks. Granovetter’s subtle, nuanced theory has spawned countless follow-on ideas, many of which are immortalized in the 35,000 manuscripts that cite the original work. Among these are notable theories in their own right, such as Ron Burt...

When Jim Cramer offers investment advice on his CNBC show Mad Money, he influences market prices (Engelberg et al., 2009). By analyzing text from transcripts of the show, we explore the relationship between what Cramer says and the magnitude and direction of his price effect. We demonstrate that Cramer’s influence is more complex than simply drawin...

Randomized experiments, made possible by the digitization of human interaction at population scale, can dramatically improve our understanding of market trends, the adoption and diffusion of health behaviors, the productivity of information workers, and whether particular individuals in a social network have disproportionate influence. I also addre...

Aral discusses the newly emerging capability to rapidly deploy and iterate micro-level, randomized, and large-scale experiments in complex social and economic settings at the population scale. Large scale experiments, conducted on millions or hundreds of millions of people, allow researchers to unpack the heterogeneity of effects across different s...

We leverage the newly emerging business analytical capability to rapidly deploy and iterate large-scale, microlevel, in vivo randomized experiments to understand how social influence in networks impacts consumer demand. Understanding peer influence is critical to estimating product demand and diffusion, creating effective viral marketing, and desig...

The Strength of Weak Ties and Brokerage Theory rely on the argument that weak bridging ties deliver novel information to brokers. Yet our conceptualization of novelty itself is fundamentally underdeveloped. We therefore develop a theory of how three distinct types of novelty - diversity, total non-redundancy and uniqueness - combine with network st...

Business analytics systems are seen by many to be a growing source of value and competitive advantage for businesses. However, it is not clear if increasingly advanced analytical capabilities create opportunities for radical change in business or just represent an incremental improvement to existing systems. What are the key questions that research...

Content and identity are inextricably linked in social media. Facebook, Twitter, Linkedin, Pinterest, Reddit, Netflix and Amazon all provide identity cues that affect users’ link formation decisions and choices about who to follow for the best content, the automated friend suggestion algorithms developed by the platforms themselves, as well as new...

Reddi's thoughtful comments highlight the importance to global health policy of understanding the spread of health behaviors in society. Social media sites and online communication platforms are becoming increasingly popular sources for the dissemination of health information about prevention,

Digital technologies have made networks ubiquitous. A growing body of research is examining these networks to gain a better understanding of how firms interact with their consumers, how people interact with each other, and how current and future digital artifacts will continue to alter business and society. The increasing availability of massive ne...

Companies increasingly rely on “network” and “viral” marketing within their communication strategies. This study showed that providing viral products with specific features can increase their diffusion substantially. Products that were enabled to send automated notifications within a user’s local Facebook network upon adoption generated a 450 % hig...

Follow the Leader? The Internet has increased the likelihood that our decisions will be influenced by those being made around us. On the one hand, group decision-making can lead to better decisions, but it can also lead to “herding effects” that have resulted in financial disasters. Muchnik et al. (p. 647 ) examined the effect of collective informa...

The canonical design of customer satisfaction surveys asks for global satisfaction with a product or service and for evaluations of its distinct attributes. Users of these surveys are often interested in the relationship between global satisfaction and ...

Most models of social contagion take peer exposure to be a corollary of adoption, yet in many settings, the visibility of one's adoption behavior happens through a separate decision process. In online systems, product designers can define how peer exposure mechanisms work: adoption behaviors can be shared in a passive, automatic fashion, or occur t...

Most models of social contagion take peer exposure to be a corollary of adoption, yet in many settings, the visibility of one's adoption behavior happens through a separate decision process. In online systems, product designers can define how peer exposure mechanisms work: adoption behaviors can be shared in a passive, automatic fashion, or occur t...

Social media are fundamentally changing the way we communicate, collaborate, consume, and create. They represent one of the most transformative impacts of information technology on business, both within and outside firm boundaries. This special issue was designed to stimulate innovative investigations of the relationship between social media and bu...

We use data on a real, large-scale social network of 27 million individuals interacting daily, together with the day-by-day adoption of a new mobile service product, to inform, build and analyze data-driven simulations of the effectiveness of seeding (network targeting) strategies under different social conditions. Three main results emerge from ou...

We use data on a real, large-scale social network of 27 million individuals interacting daily, together with the day-by-day adoption of a new mobile service product, to inform, build, and analyze data-driven simulations of the effectiveness of seeding (network targeting) strategies under different social conditions. Three main results emerge from o...

Understanding peer influence in networks is critical to estimating product demand and diffusion, creating effective viral marketing, and designing ‘network interventions’ to promote positive social change. But several statistical challenges make it difficult to econometrically identify peer influence in networks. Though some recent studies use expe...

The Strength of Weak Ties and Brokerage Theory rely on the argument that weak bridging ties deliver novel information to brokers. Yet, very little empirical evidence exists to validate this claim. Analyzing an evolving corporate email network, we investigate the dynamic mechanisms that enable the “vision advantage”. Three results emerge. First, we...

Digital technologies have made networks ubiquitous. A growing body of research is examining these networks to gain a better understanding of how firms interact with their consumers, how people interact with each other, and how current and future digital artifacts will continue to alter business and society. The increasing availability of massive ne...

A Facebook message sent out during the 2010 US congressional elections influenced the voting behaviour of millions of people. The experiment illustrates the power of digital social networks to spread behavioural change. See Letter p.295

Many theories address how IT affects the number of suppliers and supply chain governance. However, their predictions are at times contradictory and there is relatively little empirical evidence with which to evaluate them. We therefore develop an integrated, multi-period model of the optimal number of suppliers that combines search and coordination...

Identifying social influence in networks is critical to understanding how behaviors spread. We present a method that uses in vivo randomized experimentation to identify influence and susceptibility in networks while avoiding the biases inherent in traditional estimates of social contagion. Estimation in a representative sample of 1.3 million Facebo...

The recent availability of massive amounts of networked data generated by email, instant messaging, mobile phone communications, micro blogs, and online social networks is enabling studies of population-level human interaction on scales orders of magnitude greater than what was previ ously possible.1'2 One important goal of applying statistical inf...

We econometrically evaluate information worker productivity at a midsize executive recruiting firm and assess whether the knowledge that workers accessed through their electronic communication networks enabled them to multitask more productively. We estimate dynamic panel data models of multitasking, knowledge networks and productivity using severa...

Researchers have recently been able to understand organizations at an unprecedented level of detail using new digital records and electronic communication data. However, while digital communication is important in the modern workplace, face-to-face interaction still represents a large and important share of organizational communication, information...

Professors Iyengar, Van den Bulte and Valente (2010) (hereafter IVV) make deep nuanced contributions to our understanding of how opinion leadership and social contagion affect the adoption and diffusion of new products. Their work moves us forward not only by answering several fundamental questions at the heart of diffusion research, but also by hi...

Managers and researchers alike suspect that the vast amounts of qualitative information found in blogs, product reviews, real estate listings, news stories, analyst reports and experts’ advice influence consumer behavior. But, do these kinds of qualitative information impact or rather reflect consumer choices? We argue that message content and cons...

We examine how firms can create word-of-mouth peer influence and social contagion by designing viral features into their products and marketing campaigns. To econometrically identify the effectiveness of different viral features in creating social contagion, we designed and conducted a randomized field experiment involving the 1.4 million friends o...

Revolutions in measurement inevitably revolutionize science and practice. Over 300 years ago, Anton van Leeuwenhoek developed a better microscope to verify thread counts on imported carpets. Using this new tool, he discovered microorganisms he called “animalcules” in drops of water and individual blood corpuscles in drops of blood. Biology and medi...

We test for three-way complementarities among information technology (IT), performance pay, and human resource (HR) analytics practices. We develop a principal–agent model examining how these practices work together as an incentive system that produces a larger productivity premium when the practices are implemented in concert rather than separatel...

The authors propose that a tradeoff between network diversity and communications bandwidth regulates the degree to which social networks deliver non-redundant information to actors in brokerage positions. As the structural diversity of a network increases, the bandwidth of the communication channels in that network decrease, creating countervailing...

Node characteristics and behaviors are often correlated with the structure of social networks over time. While evidence of this type of assortative mixing and temporal clustering of behaviors among linked nodes is used to support claims of peer influence and social contagion in networks, homophily may also explain such evidence. Here we develop a d...

A field is emerging that leverages the capacity to collect and analyze data at a scale that may reveal patterns of individual and group behaviors. Government Version of Record

We find three-way complementarities among IT, performance pay, and monitoring practices. We model these practices as a tightly-knit incentive system that produces the largest productivity premium when implemented in concert. We assess our model by combining fine-grained data on Human Capital Management (HCM) software adoption with detailed survey d...

A tension exists between two well-established streams of literature on the performance of teams. One stream contends that teams with diverse backgrounds, social structures, knowledge, and experience function more effectively because they bring novel information to bear on problems that cannot be solved by groups of homogeneous individuals. In contr...

IntroductionDo Social Networks Matter?Knowledge Management ApplicationsFuture Research and TrendsReferences

This paper investigates how information flows enable social networks to constitute social capital. By analyzing the information content encoded in email communication in an executive recruiting firm, we examine the long held but empirically untested assumption that diverse networks drive economic performance by providing access to novel information...

Social network theories (e.g. Granovetter 1973, Burt 1992) and information richness theory (Daft & Lengel 1987) have both been used independently to understand knowledge transfer in information intensive work settings. Social network theories explain how network structures covary with the diffusion and distribution of information, but largely ignor...

I examine how information technology (IT) skills and use, communication network structures, and the distribution and flow of information in organizations impact individual information worker productivity. The work is divided into three essays based on the task level practices of information workers at a midsize executive recruiting firm: Essay 1: "...

Despite evidence of a positive relationship between information technology (IT) investments and firm performance, results still vary across firms and performance measures. We explore two organizational explanations for this variation: differences in firms' IT investment allocations and their IT capabilities. We develop a theoretical model of IT res...

We examine what drives the diffusion of different types of information through email networks and the effects of these diffusion patterns on the productivity and performance of information workers. In particular, we ask: What predicts the likelihood of an individual becoming aware of a strategic piece of information, or becoming aware of it sooner?...

Despite evidence of a positive relationship between IT investments and firm performance, results still vary across firms and performance measures. We explore two organizational explanations for this variation: differences in firms' IT investment allocations and IT capabilities. We develop a theoretical model of IT resources, defined as the combinat...

We examine the diffusion of different types of information through email networks and the effects of these diffusion patterns on the performance of information workers. In particular, we ask: What predicts the likelihood of individuals becoming aware of a new piece of information, and how quickly they obtain it? Do different types of information ex...

This paper calculates indices of central bank autonomy (CBA) for 163 central banks as of end-2003, and comparable indices for a subgroup of 68 central banks as of the end of the 1980s. The results confirm strong improvements in both economic and political CBA over the past couple of decades, although more progress is needed to boost political auton...

Although IT portfolio management has been a best practice for some time, many companies are still getting returns from IT investments that are below their potential. New studies show that a measureable premium can be gained by implementing a set of interlocking business practices and processes, collectively called IT savvy.

While it is now well established that IT intensive firms are more productive, a critical question remains: Does IT cause productivity or are productive firms simply willing to spend more on IT? We address this question by examining the productivity and performance effects of enterprise systems investments in a uniquely detailed and comprehensive da...

Information technology is major investment for most enterprises and constitutes a portfolio of investments. Just like any other investment portfolio, the IT portfolio must be balanced to achieve alignment with business strategy and the desired combination of short and long term pay off. This portfolio balancing is the role of senior management and...

We investigate the long held but empirically untested assumption that diverse networks drive performance by providing access to novel information. We build and validate an analytical model of information diversity, develop theory linking network structure to the distribution of novel information among actors and their performance, and test our theo...

We explore new methods of mining and analyzing organizational information flows and individual information worker productivity. We extract and link corporate email data to accounting data on employee performance to test relationships between social network structures, information structures, and the performance and productivity of individual employ...

We find evidence of three-way complementarities among information technology (IT), performance pay, and monitoring practices. We develop a principal-agent model examining how these practices work together as an incentive system that produces the largest productivity premium when the practices are implemented in concert. We assess our model by combi...