I have a graph that over time new nodes can be added to it and new links between nodes can be added. at any given time t, I create a network using all nodes and edges up to time t and calculate the page rank of each node. For time t+1, I take all the nodes and edges up to time t+1 (so this network includes all the nodes and edges in the graph that was made at time t and possibly some new nodes and edges) and then calculate the page rank of the nodes again. Now let's say the PageRank of node n1 at time t is x1, and the PageRank of the same node n1 at time t+1 is x2. What is an appropriate way to compare x1 and x2 given that they have been obtained from two different graphs? I would like to be able to say if the PageRank of a node has increased or decreased over time.
Consider a scenario in which a node has scored .6 in a network made at time t and the majority of other nodes scored .1 or less. The same node scores .6 in a network made at time t+1 but now the majority of other nodes score closer to .01. Is it fair to say this node's centrality rank(pagerank) has stayed the same given that the network t and network t+1 are so different?