Modularity compares the actual number of edges inside communities with the expected number of edges. The expected number of edges is calculated with a null model that assumes random wiring process in the whole network. As a result, the size of network determines the minimum size of community that the modularity can identify.
Papers to read #
- Narrow scope for resolution-limit-free community detection
- The map equation and the resolution limit in community detection
- Santo Fortunato and Marc Barthélemy (2007). "Resolution limit in community detection". PNAS 104: 36-41. doi:10.1073/pnas.0605965104. http://www.pnas.org/content/104/1/36