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Library · Methods

AI screening

Three modules help people find what to look at. None produces an emissions figure, none decides anything, and every output is a question for a named reviewer, carrying its model version and the signals behind it.

The rules every module follows

These are enforced in code, not stated as intentions: a module that crosses one raises an error instead of shipping a claim the data cannot carry.

Record level only
The evidence base is three facilities over roughly 27 field-years at monthly resolution: a substantial physical dataset and a thin statistical one. Modules work on facility-months and observations, never on facility-level statistical claims.
Physics forecasts
The decline-curve and gas-balance projection is the forecast. Statistical methods characterise its error; none extrapolates a trend.
No headline figures
No AI output is an emissions figure. Each enters the review queue with an explanation and a model version.
A person decides
A reviewer confirms, explains or dismisses each item with a written note, recorded in the audit trail with the state before and after.
An AI question is not a finding. A compressor trip, a planned shutdown and a mis-keyed column look the same to a detector. Only an operator can say which it was.

The modules

Read live from the model registry: the version in service and the guards that bound it.

anomaly

live

anomaly-robust-z+iforest-1.0.0

Is a month unusual for this facility?

A robust z-score on the seasonally adjusted residual of flaring, venting, fuel use and methane performance is the gate: it applies an absolute criterion, so a series with no unusual months raises nothing. An isolation forest corroborates a point the gate has already flagged and never flags on its own. Median and median absolute deviation throughout, so one genuine outlier cannot hide the next.

Output: A question in the review queue, with the ranked signals behind it and the model version.

z threshold
3.5
min records
36
gate
robust z on the seasonal residual; the isolation forest corroborates only

reconciliation

live

reconciliation-1.0.0

Does a satellite retrieval over a facility disagree materially with the inventory?

Matches each top-down retrieval to a facility and period and scores the divergence against the bottom-up figure. A retrieval cannot attribute to a process, sees only large emitters under good conditions and samples an instant, so it cross-checks the inventory and never replaces it.

Output: A question in the review queue when the divergence is material; the inventory figure is unchanged either way.

material divergence pct
50

triage

not live

triage-gbdt-1.0.0

Of the returns that passed every rule, which should a reviewer open first?

A gradient-boosted tree over engineered, record-level features, with an attribution for each. It orders a reviewer's attention; it never blocks a return (the deterministic rules do that) and never produces a figure. Until enough reviewed outcomes exist it is not trained, and the queue falls back to a stated ordering by severity and age.

Output: A priority on each queue item, labelled with whether it came from the model or the fallback order.

min labelled reviews
200
requires both outcomes
yes

How the modules are evaluated

Weekly, the platform counts what each module raised — per metric, per year, and as a share of facility-months — and how reviewers decided it.

Reviewer agreement is the share of decided AI questions confirmed as an issue, and the share confirmed or explained — a question worth asking even when the answer was benign. Neither is reported until thirty decisions exist: a precision over a dozen reviews would be read as a property of the model when it is noise.

A flag rate that jumps after a model change, or one metric that dominates, shows in the backtest before anyone has to notice it in the queue.

NextThe assistantWhat it answers, what it refuses, how it is tested