🌻 Reporting global and local network statistics
4 Nov 2025
Summary#
This extension is about summarising a causal map as a network using simple statistics.
It can be useful for evaluation work because it helps you move from:
- “here is the picture” → to
- “here are a few headline properties of the picture”.
When to use it#
- Reporting: you want a short paragraph or slide that characterises the map (dense vs sparse, highly central factors, etc.).
- Comparing views: you want to compare two filtered views (e.g. before/after simplification, or one group vs another) using the same set of stats.
- Sanity checks: you want to spot oddities (e.g. one “hub” factor connected to everything because of a label issue).
What kinds of stats are most interpretable#
Global (“whole map”) summaries#
- Number of factors / links: basic size of the current view.
- Density / sparsity: how connected the map is relative to how many factors it contains.
- Share of self-loops (if present): how much “plain coding” or A→A evidence is in view.
Local (“per factor”) summaries#
- In-degree / out-degree: how many incoming vs outgoing links a factor has (as outcome vs as driver).
- Centrality (use carefully): identifies “connector” factors that sit on many paths.
How to interpret them (practical cautions)#
- These are properties of the current filtered view (sources selection + analysis filters). Change the pipeline and the stats change.
- Network stats measure structure, not “truth” and not causal effect size.
- Centrality can be inflated by label choices (e.g. a very broad parent label used as a bucket).
- For group comparisons, it’s usually better to compare like-for-like pipelines (same transforms, same simplification rules), otherwise the stats conflate analytic choices with group differences.
Formal notes (optional)#
If you want the more formal network picture:
- Build a directed graph \(G = (V,E)\) from the current links table (after bundling / transforms as appropriate).
- \(V\) are factor labels; \(E\) are directed edges (cause→effect).
- Common global stats include \(|V|\), \(|E|\), and density (e.g. \(|E|/(|V|(|V|-1))\) if you treat it as a simple directed graph without self-loops).
- Common local stats include in-degree, out-degree, and centrality measures (betweenness, closeness, eigenvector/PageRank variants). These can be computed on the simple graph or on a weighted graph (e.g. weighting edges by source count or citation count).