Hi Fran. Thanks for posting your question.
The survey tool assumes that each person answers each question no more than once, so there is no adding to be done. The only possible data about Atkins going to Blair for problem solving is what Atkins said on the survey. It is theoretically possible that we'd ask everybody what they think: "Does Atkins go to Blair for problem solving?" But that is (almost) never done in a network survey. Very different than a "normal" survey!
Furthermore, because the case study data is published in Yes-No form, we have chosen to represent "No" as 0 and "Yes" as 3. If Hansen and Krackhardt had collected and published scalar data, we could have incorporated that into the spreadsheet, but all we have is Yes-No data.
Finally, just in case there is any confusion, note that each row of the spreadsheet indicates the responses of that person. In the example below, Atkins says that he goes to Calder for problem solving. Calder does not say anything about going to Atkins
