If you want to analyze the structure of an innovation network you are often faced with the problem that you have two-mode data, e.g. you have data of firms that collaborate in a common R&D project. That is, each firm is connected to the project (Figure 1).We assume that if firms participate in the same project, then they interact with each other. So we need a projection of a two-mode network into a one-mode network where the actors are linked to each other (Figure 2).This can be done by the igraph package. A small example dataset can be downloaded here: example1.
# load the igraph package library ("igraph") # load the example dataset data <- read.csv2("example1.csv", header = T) # create an igraph object net <- graph.data.frame (data, directed = F) # plot the two-mode network, firms are connected # to the projects plot (net) # add a "type" variable to indicate that we have # two-mode network V(net)$type<- V(net)$name %in% data [,1] # project the two-mode into a one-mode network net.p <- bipartite.projection(net)$proj2 # plot the projected network plot (net.p)