System

Question in.Design out.

Each decision constrains the next, so the engine works in order rather than all at once. The start date governs eligibility. Eligibility governs the comparison. The comparison governs what the analysis has to account for. Step through the sequence below.

01 Restate

Decides
Constrains next
Start Date

The start date isweighed, not assumed.

Follow-up has to begin somewhere, and the wrong choice bakes in bias that no later analysis can remove. Each candidate is assessed on whether eligibility is knowable at that moment, whether treatment can be assigned there, whether follow-up can begin there, and what it risks. Discharge, for instance, looks convenient and quietly excludes everyone who died first.

Candidate start date
Eligibility known
Assignment possible
Follow-up can start
Immortal time risk
Default
First treatment order
Yes
Yes
Yes
Low
Preferred
First eligible lab value
Yes
Usually
Yes
Low
Preferred
Diagnosis confirmation
Yes
Usually
Yes
Low
Preferred
Qualifying procedure
Yes
Yes
Yes
Low
Preferred
Hospital admission
Usually
Sometimes
Yes
Moderate
Acceptable
First administration
Usually
Yes
Yes
Moderate
Acceptable
ICU admission
Usually
Usually
Yes
Moderate
Caution
Symptom onset
Rarely
Rarely
Sometimes
High
Caution
Study enrolment
Yes
Usually
Yes
Low
Caution
Hospital discharge
Yes
Sometimes
Yes
High
Avoid

Ten candidate anchors, each with its own scoring profile. A default is a starting point, not a verdict: the engine states which one it chose for your question and why the others were rejected.

Eligibility

Every criterionis a cut.

Cohorts are usually assembled from whichever filters a query happened to contain, and the attrition is reconstructed afterwards if anyone asks. Emulation forces each criterion to be a stated rule, applied once, at a defined moment, with what it removed recorded as it happens.

Adults, 18 and over−12,410
Qualifying primary diagnosis−38,207
No prior enrolment−6,842
Treatment ordered in window−2,133
Screened
61,532
Excluded
0
Analytic cohort
61,532
0 of 4 applied · Illustrative

Figures shown are invented for illustration. The engine writes the criteria and the rules for applying them; the counts come from running those rules against your own data.

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Demo ourservices.

TriEmulate is enterprise infrastructure under active development and is not yet generally available, but it runs today and can be walked through end to end on a question of your own. A United States provisional patent application covering the system was filed in September 2026. If you work on causal inference in health data, bring a question and we will put it through.