Cumulative frequency and temporal network slices

Dec 8, 2009 at 7:37 PM

Hello. Thanks for NodeXL, it's a wonderfully intuitive SNA tool.

I am analyzing a large matrix of interorganizational email exchanges that took place across multiple working groups (wg), over time. My nondirected, essentially two-mode matrix looks like this:

(name of group) wg1, wg2…. (orgs name) org1, org2…. (frequency) 80, 7… (year) 1999…2009

Two problems:  

(1) Cumulative frequency: Importing the matrix to NodeXL does not take into account the cumulative frequency (i.e. "strength") for each vertex in a given year. For example, org 1 sent 30 messages to wg1 and 40 to wg3, so its cumulative frequency should be 70. What NodeXL takes now is the individual frequency of 30.

(2) Network slices by year: I could not figure how to do that. Dynamic filters that consider a year at a time did not see to work. Instead, NodeXL considers all of the years, combined.  

Any suggestions? 

Much appreciated,


Dec 9, 2009 at 4:39 AM
Edited Dec 9, 2009 at 4:42 AM


1. Are you using NodeXL's Import, Data, Import, From Open Matrix Workbook feature to import the matrix?  If so, NodeXL interprets the numbers in the matrix as edge weights and copies them to an Edge Weight column on the Edges worksheet.  I'm not sure how a cumulative frequency scheme would work, but that's not what NodeXL does.

2. On the year issue, I'll assume that you have a date column named "My Date" on the Edges worksheet, and you want to dynamically filter the edges by year.  (The following holds for vertices as well; just use the Vertices worksheet instead.)  Do this:

  • Add a column to the right edge of the Edges table and call it "Year".  (You can just overwrite the "Add Your Own Columns Here" column header with "Year" to accomplish this.)
  • In the new column's first data cell, enter the formula "=YEAR(Edges[[#This Row],[My Date]])".  That will copy the year portion of the dates from the My Date column to the Year column.
  • In NodeXL, Analysis, Dynamic Filters, the Year column will appear in the Edge Filters section.  Adjust the filter's sliders and range bar to specify the years for which you want edges to show in the graph.

Or did I misunderstand what you're trying to do with dates?

-- Tony