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WEEK 12 – EXERCISE #4 Two-Mode Networks (20 points) – INSTRUCTIONS Due Friday 11/10

This exercise is divided in two parts. To complete the first part, please review this week’s material and answer the question. In the second part, I ask you to work with a relatively big set of nodes on American business networks, and compute network transformations on this set. This exercise is adapted from J. Cook “SOC/COM 375” class. To successfully complete this part, Excel is required and Gephi is optional.

PART I (5 points)

In the article “The Duality of Persons and Groups”, Ronald Breiger explains “the intersections of persons within groups and of groups within individuals” (p.181). Please, in about half a page, describe how two- mode networks work, and explain their sociological relevance. Make sure to use the lecture material.

About 1⁄2 a page, single space. Provide the reading’s page number for reference.

PART II (15 points)

  1. Go to “Fortune 500” webpage: 500 US big corporations are registered to this site http://fortune.com/fortune500/

  2. Pick 6 of these 500 corporations: at least 3 must be different from those showed in the video (see point 5 for the video). For each of them find the list of the people sitting on the Board of Directors.

  3. Find the Board of Directors of the six corporations you selected. To find it:

    •   Click on the corporation’s profile on Fortune 500. Toward the bottom of each company’s

      profile there is a link to the company webpage. Follow the link: the information about the

      Board of Directors will be on the company webpage

    •   Once you are on the company webpage, look for words such as: Investors, Investor

      Information, About, or Corporate Governance. Every website has a different path and organization, click the more specific links until you find words such as Board of Directors, Directors, Leadership or similar words that indicate the Board of Directors

    •   For example, to find Walmart Board of Directors: check at the very bottom of Walmart main webpage until you find Get to know us, click on Corporate, then, in a new page, click on Leadership, and finally Board of Directors (not to be confused with Executive Management)

    •   Most corporations have information on their Board of Directors online, be patient and explore the website. If you do not find anything after about 10 minutes of search, change corporation

  4. Manually type in the information about each of the 6 companies in an Excel spreadsheet. Enter the data as a two-mode matrix, exactly as shown in the video (see point 5): columns are companies and rows are members of boards. Enter all board members names with the same formatting. For example, if you start with Last Name, First Name use this format for all 6 companies.



  1. Watch this video tutorial to transform your network from 2 to 1 mode using Excel:
    J. Cook “Social Networks: Converting a 2-Mode Matrix to 1-Mode Matrices in Excel” (26:13)
    The video walks you through the process step by step:

    •   In the first 10 minutes, the video shows how to convert the network from 2 to 1 mode by hand; this method is a little tedious but is good practice

    •   In the second part, the video shows how to convert the network automatically, using matrix multiplication in Excel. This second option is the most efficient way to convert two mode networks into one mode networks

  2. At this point you should have a persons by persons 1 mode matrix, a corporations by corporations 1 mode matrix, and the original persons by corporations 2 mode matrix. What you accomplished is a matrix multiplication of your original 2 mode matrix, good job!

  3. Visualize the corporations by corporations matrix as network graph. Important: visualize only this 1 mode matrix, not the other one. You can visualize it:

    •   By hand: draw the network on a piece of paper (then take a picture and copy and paste it into a document) or use power point or similar tools. Make sure to indicate tie strength among nodes by simply adding the number on the tie, as shown in Breiger’s 1974 article

    •   With Gephi: before uploading the data in Gephi, remember to transform your corporations by corporations matrix into an edge list and node list (review the tutorial posted on Week 1: https://www.youtube.com/watch?v=HJ4Hcq3YX4k), and to save the two lists as .csv files, otherwise Gephi won’t read them

  4. Describe your results in min 1 page and max 1 1⁄2 page.
    Describe the
    corporations by corporations matrix and network graph, and the persons by persons matrix. Be as much accurate as you can in describing the two matrices, and make sure to use and quote this week’s material.

By Friday 11/10 at 11:59 PM, submit to the “Exercise #4” folder the following:

  •   One Excel file containing three matrices, one matrix per sheet: the original 2 mode persons by corporations affiliation matrix, your 1 mode persons by persons matrix, and your 1 mode corporations by corporations matrix. All Excel tabs/sheets must be properly labeled, as shown in the video

  •   One single document containing the following: your answer to the question of part I of this exercise (half a page); a graphic representation of the corporations by corporations matrix (in the format you picked at point 7); the description of the two 1 mode matrixes (see point 8)

    Good luck! Feel free to email me if you have questions