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Feature Importance Share Calculator

Work out feature importance share instantly with clear inputs, formula shown and shareable results.

About Feature Importance Share Calculator

Tree-based importances and SHAP magnitudes are only meaningful relative to the total, so a raw gain of 0.32 says nothing until you know the sum. Comparing a feature's share against the even share of 1/p exposes genuine dominance: a feature carrying 10 times the average share is doing most of the work, and is also where leakage usually hides.

Formula

Importance share

share = feature importance / total importance; even share = 1 / feature count; ratio = share / even share

Worked example

With the default values below, Feature Importance Share Calculator returns Share of total importance of 32.00%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Importance of the featureminimum 0
0.32
Sum of all importancesminimum 0.001
1
Number of features in the modelminimum 1
40

Results

Share of total importance
32.00%
Share if every feature mattered equally
2.500%
Times more important than an average feature
12.80
Importance held by all other features
68.00%

Step by step

  1. 1Values used
  2. 2Importance share
  3. 3Share of total importance= 32.00
  4. 4Share if every feature mattered equally= 2.500
  5. 5Times more important than an average feature= 12.80
  6. 6Importance held by all other features= 68.00

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why does one feature dominate?

Either it genuinely carries the signal, or it leaks the target. An ID, a timestamp or a post-outcome field with an extreme share should always be investigated before shipping.

Are gain importances reliable?

They are biased toward high-cardinality features. Permutation importance or SHAP values on held-out data give a fairer ranking.

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Feature Importance Share Calculator | Calcrivo