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Outcome-Conditional Sample Information

The experimental outcome_conditional_sample_information_value API reports what a proposed finite measurement may be worth for each possible outcome, rather than reporting EVSI alone.

import json
from pathlib import Path


from voiage import outcome_conditional_sample_information_value


request = json.loads(
    Path(
        "specs/frontier/outcome-conditional-sample-information/v1/fixtures/"
        "normative/input.json"
    ).read_text()
)
result = outcome_conditional_sample_information_value(request).to_contract_dict()


print(result["aggregate"]["evsi"])
print(result["aggregate"]["sigma_vsi"])
print(result["aggregate"]["low_value_risks"])

For each outcome x, delta_ev is the direction-aware shift in the posterior optimal system objective, while vsi is the nonnegative posterior gain over the declared baseline-optimal reference action. Their expectations both equal EVSI; their outcome-wise values, variances, standard deviations and tails do not generally agree.

sigma_vsi is Equation 10’s predictive-probability-weighted population standard deviation (ddof = 0). It is not the unweighted sample standard deviation used by the paper’s supplementary MATLAB/Table 3 calculation. low_value_risks reports P(VSI_x <= delta) for every declared nonnegative threshold. When policies tie, this probability is deliberately separate from reference-action exclusion, mandatory switching, and complete tie-set change. tie_tolerance is expressed in the declared value unit; probability tolerance is never used to truncate value metrics or Equation 10 dispersion. A lower-tail mass of zero reports the limiting finite essential minimum.

Run the same strict contract from the CLI:

Terminal window
voiage --format json calculate-outcome-conditional-sample-information request.json

The result is bound to a canonical input digest and can be reconstructed without the original runtime object. Continuous outcomes, fitted-estimator calibration, dynamic/adaptive sampling, underlying-system risk, Rust/R/Julia execution, stable promotion and scientific approval remain unsupported gates.