NYU Stern School of Business

Undergraduate College

MULT-UB.0038.001 (C70.0038): Networks, Crowds and Markets

Spring 2012

Instructor Details

Sundararajan, Arun



KMC 8-93


Guest Sessions taught by: Sinan Aral, Yannis Bakos, Panagiotis Ipeirotis, Foster Provost

Administrative Contact: Shirley Lau (shirley.lau@stern.nyu.edu)


Course Meetings

MW, 11:00am to 12:15pm

Tisch T-LC21

Final Exam:

Schedule exceptions
    Class will not meet on:
    Class will meet on:


Course Description and Learning Goals


This is a course on how the social, technological, and natural worlds are connected, and how the study of networks sheds light on these connections. Topics include: social network structure and its effects on business and culture; crowdsourcing; games on graphs; the propagation through networks of information, fads and disease; small worlds, network effects, and "rich-get-richer" phenomena; the power of networks for prediction; the power of the network for web search; networks and social revolutions, and the melding of economics, machine learning, and technology into new markets, such as "prediction markets" or markets for on-line advertisements.

The class will be a combination of lectures based on the textbook and guest lectures from well-known experts on these topics, primarily Stern faculty (a well-known center of excellence for research on networks, crowds, and markets).

One main goal of this class is to work our way through most of the new, acclaimed textbook:
Networks, Crowds, and Markets: Reasoning About a Highly Connected World, by David Easley and Jon Kleinberg.

The textbook readings will be complemented with classic and recent research papers.


Course Outline


Focus and interaction
This is primarily a lecture-based course (there are no cases or case discussions), but student participation is an essential part of the learning process in the form of active discussion. I will expect you to be prepared for class discussions by having read the required readings and having satisfied yourself that you understand what we have done in the prior classes. You are expected to attend every class session, to arrive prior to the starting time, to remain for the entire class, and to follow basic classroom etiquette, including having all electronic devices turned off and put away for the duration of the class (this is Stern policy) and refraining from chatting or doing other work or reading during class.

The Blackboard site for this course will contain any lecture notes (we will not attempt to duplicate material in the book), reading materials, assignments, extra-class discussions, and late-breaking news. You should use the Blackboard discussion board to ask any questions you have about class material, and you should try to answer your classmates’ questions. Your class participation grade will include your contributions to the discussion board. You will not be penalized for being wrong in trying to participate on the discussion board (or in class).

I will use Blackboard as a primary means of communication. It is your responsibility to check Blackboard (and your email) at least once a day during the week (M-F), and you will be expected to be aware of any announcements within 24 hours of the time the message was sent. I will assume that you have read all
announcements and class discussion.

As far as is possible, rather than emailing us, you should post your questions on the relevant Blackboard discussion forum. This is far more efficient than individual back-and-forth email. There are two discussion forums currently active:
1. Administrative questions about the course
2. General questions and comments about what we cover in class

Before posting a question, make sure that you read through the course content on Blackboard, the frequently-asked-questions, and the questions other students have posted. Often, you will find the answer to your question here.

I will check my email at least once a day during the week (M-F). I receive a tremendous amount of email (currently, I have over 44,000 unread messages in my Inbox), and cannot process it all daily. Your email will get priority if you include the special tag ([NCM]) in the subject header. I sort/filter based on this tag in order to make sure to process class mail first. I do not guarantee to be able to process your email within 24 hours but your chances are vastly improved if you use the special tag.

In general, we will follow Stern default policies unless I state otherwise. This is especially important for non-Stern students to understand. I will assume that you have read them and agree to abide by them.

Class participation
The classroom discussion presents a unique opportunity for you to develop and enhance your confidence and skills in articulating a personal position, sharing your knowledge, and reacting to new ideas. All of you have personal experience with the subject matter that can enhance our understanding of the it, and that we want to encourage you to share.

The grade we assign for your class participation is a careful, subjective assessment of the value of your input to classroom learning. We keep track of your contributions towards each class session, and these contributions can include (but are not restricted to) active participation in classroom group activities, raising questions that make your classmates think, providing imaginative yet relevant analysis of a situation, contributing background or a perspective on a classroom topic that enhances its discussion, and simply answering questions raised in class.

Emphasis is placed on the quality of your contribution, rather than merely on its frequency. A lack of preparation, negative classroom comments or inappropriate classroom behavior (talking to each other in class, walking in and out of class when the session is in progress, or sleeping in class, especially if
accompanied by loud snoring) can lower this grade.


Assessment Components


Requirements and grading
At NYU Stern we seek to teach challenging courses that allow students to demonstrate differential mastery of the subject matter. Assigning grades that reward excellence and reflect differences in performance is important to ensuring the integrity of our curriculum. I expect that students will become engaged with this course and do excellent or very good work, receiving As and B+’s. Note that the actual distribution for this course and your own grade will depend upon how well each of you actually performs this particular semester—invariably there are students who do not put in the necessary effort and get grades below what
they otherwise would expect.

During this course, you will be assigned four individual assignments and one group project. You will have a final examination. You are expected to participate in classroom and online discussions. The breakdown of points (out of a total of 500) for each of these:
Assignments 150 points
Class Participation 75 points
Project 125 points
Final examination 150 points
Total 500 points

Assignments: Each assignment will provide you with a set of instructions and guidelines. Expect to use Excel, the Web, elementary mathematics, and pen/paper. Except as explicitly noted otherwise, you are expected to complete your assignments on your own—without interacting with other students or any materials produced by other students. Completed assignments are to be handed in on Blackboard. Answers to homework questions should be well thought out and communicated precisely, avoiding sloppy language, poor diagrams, and irrelevant discussion. In general, homework will be due the day before class by 11:59pm. Late submissions will be accepted and graded, but you will only be given credit for 50% of your score. And your carriage may turn into a pumpkin.

Examination: The examination will be closed book/notes/computer/BlackBerry/iPod/iPhone/iPad/iProfessor. We will discuss its format in due course.

Project: Group projects should be done in groups of 5 students. After week 2 of the course, your classmates will know you better, and this will help facilitate the group formation process. We will give you a set of detailed guidelines about working in teams. You will also be asked to evaluate the contribution of each of your team members after each group project.

Grading: If you feel that a calculation, factual, or judgment error has been made in the grading of an assignment or exam, please write a formal memo to me describing the error, within one week after the class date on which that assignment was returned. Include documentation (e.g., a photocopy of class notes). I will make a decision and get back to you as soon as I can. Please remember that grading any assignment requires the grader to make many judgments as to how well you have answered the question. Inevitably, some of these go “in your favor” and possibly some go against. In fairness to all students, your entire assignment or exam will be re-graded.

For students with disabilities: If you have a qualified disability and will require academic accommodation during this course, please contact the Moses Center for Students with Disabilities (CSD, 998-4980) and provide me with a letter from them verifying your registration and outlining the accommodations they recommend. If you will need to take an exam at the CSD, you must submit a completed Exam Accommodations Form to them at least one week prior to the scheduled exam time to be guaranteed accommodation.

Lecture notes and reading
Lecture notes: For any given class there may or may not be printed lecture notes. Often, I will simply teach on the whiteboard rather than using PowerPoint slides. You will be expected to flesh out any distributed material with your own note taking, and to ask questions about any material that is unclear to you after our class discussion. Depending on the direction our class discussion takes, we may not cover all material in the notes. If the notes and readings are not adequate to explain a topic we skip, you should ask about it on the discussion board.

Readings: The readings in the book (marked EK in the schedule) are required and are detailed on the class schedule on Blackboard. Other readings will be distributed for individual sessions, either in class or on the Blackboard site. (All of our supplementary readings will be posted on Blackboard.) You are responsible for reading these as well.

Schedule of topics
I may add or modify web-based readings from time to time. Make sure that you check the Documents and Slides section of Blackboard before every session – you will find a document for every classroom session, which will contain detailed information about pre-class readings, a copy of the class slides, and information about assignments/projects.

Date Topic Readings

Week 1

Overview, graph fundamentals EK 1.1-1.2, 2.1-2.4
Week 2 Introduction to social networks EK 3.1-3.5, “The Strength of Weak Ties”, “Structural Holes and
Good Ideas”, “Trust, Reciprocity and the Strength of Social Ties”.
Week 3 Predictive modeling and inference
with network data (Provost)
EK 4.1-4.5, “Audience Selection for Online Brand Advertising”.
Week 4 Strategic interaction 1:
coordination and public goods
EK 6.2, 6.5, 6.6, 6.9, 8.1, 8.2, “The Law of the Few”, “Public
Goods and Networks”, “Local Network Effects and Complex
Network Structure”, “From Innovation to Revolution”.
Week 5 Strategic interaction 2: markets
EK 10.1-10.5, 11.1-11.7, “Reducing Buyer Search Costs”
Week 6 Link analysis and authority EK 13, 14.1-14.6, 18.1-18.3
Week 7 Network effects and cascades EK 16.1-16.2, 17.1-17.6, 19.1-19.6, “Influencing the Influencers”,
“Complex Contagion and the Weakness of Long Ties”
Week 8 Selection and influence in
dynamic networks (Aral)
“The Spread of Obesity in a Large Social Network”, “Identification
of Endogenous Social Effects”, “Distinguishing Influenced Based
Contagion from Homophily Driven Diffusion in Dynamic Networks”
Week 9 Information flows on networks EK 16.1-16.7
Week 10 Networks and epidemics EK 21.1-21.8
Week 11 Small worlds and search EK 18.4-18.6, 20.1-20.5
Week 12 Crowdsourcing (Ipeirotis) (readings to be updated)
Week 13 Networks, markets and
EK 22.1-22.9


Group Projects

Guidelines for Group Projects

Business activities involve group effort. Consequently, learning how to work effectively in a group is a critical part of your business education.

Every member is expected to carry an equal share of the group’s workload. As such, it is in your interest to be involved in all aspects of the project. Even if you divide the work rather than work on each piece together, you are still responsible for each part. The group project will be graded as a whole:   its different components will not be graded separately. Your exams may contain questions that are based on aspects of your group projects.

It is recommended that each group establish ground rules early in the process to facilitate your joint work including a problem-solving process for handling conflicts. In the infrequent case where you believe that a group member is not carrying out his or her fair share of work, you are urged not to permit problems to develop to a point where they become serious. If you cannot resolve conflicts internally after your best efforts, they should be brought to my attention and I will work with you to find a resolution.

You will be asked to complete a peer evaluation form to evaluate the contribution of each of your group members (including your own contribution) at the conclusion of each project. If there is consensus that a group member did not contribute a fair share of work to the project, I will consider this feedback during grading.



At NYU Stern we seek to teach challenging courses that allow students to demonstrate their mastery of the subject matter.  In general, students in undergraduate core courses can expect a grading distribution where: 

Note that while the School uses these ranges  as a guide, the actual distribution for this course and your own grade will depend upon how well  you actually perform in this course.



The process of assigning grades is intended to be one of unbiased evaluation. Students are encouraged to respect the integrity and authority of the professor’s grading system and are discouraged from pursuing arbitrary challenges to it.

If you believe an inadvertent error has been made in the grading of an individual assignment or in assessing an overall course grade, a request to have the grade re-evaluated may be submitted. You must submit such requests in writing to me within 7 days of receiving the grade, including a brief written statement of why you believe that an error in grading has been made.


Professional Responsibilities For This Course




In-class contribution is a significant part of your grade and an important part of our shared learning experience. Your active participation helps me to evaluate your overall performance.
You can excel in this area if you come to class on time and contribute to the course by:




Classroom Norms


Stern Policies

General Behavior
The School expects that students will conduct themselves with respect and professionalism toward faculty, students, and others present in class and will follow the rules laid down by the instructor for classroom behavior.  Students who fail to do so may be asked to leave the classroom. 


Collaboration on Graded Assignments
Students may not work together on graded assignment unless the instructor gives express permission. 


Course Evaluations
Course evaluations are important to us and to students who come after you.  Please complete them thoughtfully.


Academic Integrity

Integrity is critical to the learning process and to all that we do here at NYU Stern. As members of our community, all students agree to abide by the NYU Stern Student Code of Conduct, which includes a commitment to:

The entire Stern Student Code of Conduct applies to all students enrolled in Stern courses and can be found here:

Undergraduate College: http://www.stern.nyu.edu/uc/codeofconduct
Graduate Programs: http://w4.stern.nyu.edu/studentactivities/involved.cfm?doc_id=102505

To help ensure the integrity of our learning community, prose assignments you submit to Blackboard will be submitted to Turnitin.  Turnitin will compare your submission to a database of prior submissions to Turnitin, current and archived Web pages, periodicals, journals, and publications.  Additionally, your document will become part of the Turnitin database.


Recording of Classes

Your class may be recorded for educational purposes


Students with Disabilities

If you have a qualified disability and will require academic accommodation of any kind during this course, you must notify me at the beginning of the course and provide a letter from the Moses Center for Students with Disabilities (CSD, 998-4980, www.nyu.edu/csd) verifying your registration and outlining the accommodations they recommend.  If you will need to take an exam at the CSD, you must submit a completed Exam Accommodations Form to them at least one week prior to the scheduled exam time to be guaranteed accommodation.


Printer Friendly Version