Edit Distribution

How evenly are edits distributed among Wikipedia editors? This page tracks four complementary inequality metrics (Gini, Theil, Palma, and Fragility) to reveal whether a wiki's output is broadly shared or concentrated in the hands of a few prolific contributors. Together they paint a picture of editorial power concentration and community resilience.

Current Gini
Current Theil
Current Palma
Fragility

Gini Coefficient Over Time

The Gini coefficient ranges from 0 (every editor contributes equally) to 1 (a single editor does everything). The dashed line at 0.5 marks the midpoint. Most active wikis sit well above 0.5, reflecting a heavy-tailed edit distribution.
How is this calculated?

Gini = (2 × Σ rank × edits_i) / (n × Total Edits) − (n + 1) / n where n = number of editors, sorted by ascending edit count, rank = 1…n

The standard Gini coefficient is applied to the distribution of edits across all active editors in each wiki and month. A value of 0 means perfect equality (every editor made the same number of edits), while 1 means maximum inequality (one editor made all edits). Gini cannot be reconstructed exactly from monthly or per-wiki summary statistics, so it is shown only when the selected period is represented by one source row. Combined periods and All wikis never report a weighted average as a global Gini.

Theil Index (Decomposable Inequality)

Unlike Gini, the Theil index can be decomposed into between-group and within-group components, making it useful for understanding whether inequality comes from differences between editor classes or within them. Higher values indicate greater concentration of edits.
How is this calculated?

Theil T = (1/n) × Σ (edits_i / mean_edits) × ln(edits_i / mean_edits)

The Theil T index is an entropy-based inequality measure. It is computed as the weighted sum of each editor's share of total edits multiplied by the logarithm of that share relative to equal distribution. Unlike Gini, Theil is perfectly decomposable: total inequality can be split into between-group and within-group components, which makes it especially useful when multiple user types are selected.

Palma Ratio (Top 10% / Bottom 40%)

The Palma ratio divides the edit share of the top 10% of editors by the share of the bottom 40%. A ratio above 1 (dashed line) means the most active decile contributes more than the bottom four deciles combined. This metric focuses attention on the tails of the distribution rather than the middle.
How is this calculated?

Palma = Edits by top 10% of editors / Edits by bottom 40% of editors

The Palma ratio is the share of total edits made by the top 10% of editors divided by the share made by the bottom 40%. A Palma ratio greater than 1 means the top decile of editors produces more output than the bottom four deciles combined. This metric was originally proposed in income inequality research because the "middle" (deciles 5-9) tends to be stable, so the real action is in the tails.

Fragility: Editors Needed for 50% of Output

This is the bus factor of the wiki: the minimum number of editors whose combined edits account for at least 50% of all output. The ratio version (% of total editors) lets you compare fragility across periods with different editor populations. A lower number means the community is more fragile: if those few editors leave, half the output disappears.
How is this calculated?

Fragility = min k where top-k editors' edits ≥ 50% × Total Edits Fragility Ratio = Fragility / Total Editors × 100%

Editors are ranked by their edit count in descending order. Starting from the most prolific editor, edits are accumulated until the running total exceeds 50% of the period's total edits. The count of editors needed to reach that threshold is the fragility index. The ratio divides this count by total active editors, making it comparable across periods with different community sizes. A lower value signals higher risk: if just a handful of editors disengage, the wiki loses half its productive capacity.