Pajek datasets
from the book

Exploratory Social Network Analysis with Pajek
Wouter de Nooy, Andrej Mrvar, Vladimir Batagelj

Modern math method diffusion.

Dataset   ModMath

Description 38 vertices (school superintendents), 76 arcs (friendship choices), no edges, no loops, no line values. 38 vertices (school superintendents), 61 edges (symmetrized friendship choices), no arcs, no loops, no line values.
ModMath_adoption.clu: classification of the (38) superintendents according to their year of adoption: 1 - 1958, 2 - 1959, 3 - 1960, etc.
ModMath.paj: Pajek project file containing all files.


complete dataset (ZIP, 1.1K)


This network concerns the diffusion of a new mathematics method in the 1950s. This innovation was instigated by top mathematicians and sponsored by the National Science Foundation of the USA as well as the U.S. Department of Education. The diffusion process was successful since the new method was adopted in a relatively short period by most schools. The example traces the diffusion of the modern math method among school systems which combine elementary and secondary programs in Allegheny County (Pennsylvania, USA). All school superintendents who were at least two years in office were interviewed. They are the gatekeepers to educational innovation because they are in the position to make the final decision. The researchers obtained data from 61 out of 68 superintendents, 51 of whom had adopted by 1963 (84%). Among other things, the superintendents were asked to indicate their friendship ties with other superintendents in the county with the following question: Among the chief school administrators in Allegheny County, who are your three best friends?
The researcher analyzed the friendship choices among the 38 interviewed superintendents who adopted the method and were in position at least one year before the first adoption, so they could have adopted earlier. Unfortunately, the researcher did not include the friendship choices by superintendents who did not receive any choices themselves; they are treated as isolates. In the original network, some friendship choices are reciprocated and others are not ( but we will use the symmetrized network ( A line in this network indicates that at least one superintendent chooses the other as his friend. The year of adoption by a superintendent's school is coded in the partition ModMath_adoption.clu: 1958 is class (time) one, 1959 is class (time) two, etc. The first adopter (v1) is a superintendent with many contacts outside Allegheny County but few friends within the county. He is a 'cosmopolite' and cosmopolites usually are early adopters but they are often too innovative to be influential in a local network.


  1. R.O. Carlson, Adoption of Educational Innovations (Eugene: University of Oregon, Center for the Advanced Study of Educational Administration, 1965, p. 19).
  2. W. de Nooy, A. Mrvar, & V. Batagelj, Exploratory Social Network Analysis with Pajek (Cambridge: Cambridge University Press, 2004), Chapter 8.


  1. Original author: Richard O. Carlson (Center for the Advanced Study of Educational Administration, University of Oregon in 1965? - not listed there now)
  2. Data compiled into Pajek data files by W. de Nooy, 2001.

2. January 2004   Pajek datasets / Exploratory SNA