Estimate randomized causal mediation

Decompose a randomized intervention into natural direct and mediated effects with optional treatment-mediator interaction, bootstrap intervals, and total-effect reconciliation.

What it's for

Explains which measured pathway carried an intervention effect while preserving a strong warning about mediator-outcome confounding.

What you give it

Every tool is a pure function: it computes from what you pass it and reads nothing on its own. Inputs split into evidence you supply from your connected systems, calibration your team owns, and numerical controls that affect precision but never the result's meaning.

Field Type Role Required
bootstrap_draws integer ≥ 200, ≤ 20000 Numerical control Optional
confidence_level number ≥ 0.8, ≤ 0.999 Your calibration Optional
feature_names array of string Evidence Optional
include_treatment_mediator_interaction boolean Your calibration Optional
observations array of objects (5 fields) Evidence Yes
ridge number ≥ 0, ≤ 100 Your calibration Optional
seed integer Numerical control Optional

Each observations record

Field Type Required
features object Optional
id string (non-empty) Yes
mediator number Yes
outcome number Yes
treatment one of "0", "1" Yes
Example input
{
  "bootstrap_draws": 200,
  "include_treatment_mediator_interaction": false,
  "observations": [
    {
      "id": "observation-0",
      "mediator": 1,
      "outcome": 4,
      "treatment": 0
    },
    {
      "id": "observation-1",
      "mediator": 3.01,
      "outcome": 15.049999999999999,
      "treatment": 1
    },
    {
      "id": "observation-2",
      "mediator": 1.02,
      "outcome": 4.1,
      "treatment": 0
    },
    {
      "id": "observation-3",
      "mediator": 3.03,
      "outcome": 15.149999999999999,
      "treatment": 1
    },
    {
      "id": "observation-4",
      "mediator": 1.04,
      "outcome": 4.2,
      "treatment": 0
    },
    {
      "id": "observation-5",
      "mediator": 3,
      "outcome": 15.05,
      "treatment": 1
    },
    {
      "id": "observation-6",
      "mediator": 1.01,
      "outcome": 4.1,

Truncated for display — the full payload is 487 lines.

What you get back

This is the actual output of running the example above — computed by the same function the platform calls, not an illustration.

Example output
{
  "assumptions": [
    "Treatment is randomized and the supplied features are measured before assignment.",
    "Conditional on treatment and supplied pre-treatment features, there is no unmeasured mediator-outcome confounding.",
    "The mediator and outcome models are linear with the declared treatment-mediator interaction and no post-treatment confounder of mediator and outcome.",
    "Pathway estimates describe the intervention mechanism at the analyzed cohort level, not individual intent or responsibility."
  ],
  "decision": "mediation_decomposition_estimable",
  "effects": {
    "decomposed_total_effect": {
      "estimate": 10.999,
      "interval": {
        "high": 11.0231,
        "low": 10.979
      }
    },
    "mediator_shift": {
      "estimate": 1.9999,
      "interval": {
        "high": 2.0053,
        "low": 1.9948
      }
    },
    "natural_direct_effect": {
      "estimate": 2.8185,
      "interval": {
        "high": 3.2312,
        "low": 2.3311
      }
    },
    "natural_indirect_effect": {
      "estimate": 8.1804,
      "interval": {
        "high": 8.6666,
        "low": 7.7802
      }
    },
    "total_effect_regression": {
      "estimate": 10.999,
      "interval": {
        "high": 11.0231,
        "low": 10.979
      }
    },

Truncated for display — the full payload is 62 lines.

How it works

Causal inference & experiment design — Separate what a change caused from what merely moved alongside it.

  1. 1 Decompose a randomized intervention into natural direct and mediated effects with optional treatment-mediator interaction, bootstrap intervals, and total-effect reconciliation.
  2. 2 Evaluate the method-specific diagnostics and gates returned by the function, then abstain unless the declared decision clears them under locally governed thresholds.

Before you trust it

Every tool in the catalog ships with the conditions under which its answer is meaningful — and the conditions under which it should abstain instead of guessing.

Assumptions & guardrails

  • Assignment or adoption timing, interference policy, overlap, attrition, and outcome availability match the estimand encoded by the method.
  • A causal label is warranted only when design and diagnostic requirements pass; otherwise treat the result as descriptive or abstain.

Minimum evidence

  • observations: required and organization-defined

How to validate it

Preserve the assignment/adoption design and validate overlap, pre-period or placebo diagnostics, attrition, interference policy, and cluster-level uncertainty; never tune on the estimated effect.

Calibrating it to your org

Same for everyone

The mathematical kernel, validation rules, method version, and JSON output semantics are organization-independent; no tenant-trained coefficients or company benchmark is embedded in the function.

Specific to you

  • metric/outcome definitions, entity grain, observation window, costs, thresholds, priors, and constraints represented by the function inputs

Calibration workflow

  1. 1 Define the management decision, target outcome, aggregate unit, privacy boundary, cadence, and prediction/intervention horizon for this organization.
  2. 2 Build a tenant-scoped historical cohort using only information available before each prediction or decision; preserve zero periods, censoring, assignment probabilities, and unresolved outcomes when the method requires them.
  3. 3 Estimate statistical parameters on training history, but obtain costs, utilities, risk tolerance, practical-effect thresholds, capacity, and policy constraints from accountable decision owners.
  4. 4 Validate on later time windows or held-out aggregate units at the deployment grain, against a simple baseline and the function-specific validation strategy.
  5. 5 Deploy only if the returned decision clears evidence, overlap, calibration, robustness, and guardrail checks; warning, unsupported, schema-gap, and fallback decisions are abstentions.
  6. 6 Monitor realized outcomes, data drift, coverage, and decision regret; recalibrate at a governed cadence or after a detected regime/definition change, never merely because a stakeholder dislikes the result.

Call it from your AI

You don't wire up 388 tools in your MCP client. The GitRevio MCP server exposes 20 tools, three of which let an agent search the catalog, read a tool's schema, and run it — so the assistant finds this one on its own.

gitrevio_capabilities_search
  { "q": "decompose a randomized intervention into natural" }
  → finds "estimate_randomized_causal_mediation"

gitrevio_capability_describe
  { "capability_id": "estimate_randomized_causal_mediation" }
  → returns the input schema and agent guidance shown on this page

gitrevio_capability_run
  { "capability_id": "estimate_randomized_causal_mediation", "arguments": { ... } }
  → returns the result shown above

Works in Claude Desktop, Claude Code, Cursor, Cline, Continue.dev, Goose and Aider. See the MCP server.

Related tools

See every tool in Causal evidence & experiments →

Ready to See Your Engineering work clearly?