The paper portfolio is an event-derived report, not a mutable balance table. Start with a fictional point grant, append synthetic fills and resolutions, then calculate current state by replay. This preserves history and makes corrections explicit.
Define event types: PORTFOLIO_CREATED, PAPER_FILL_RECORDED, MARK_TO_MODEL_RECORDED, OUTCOME_RESOLVED, EVENT_VOIDED, and CORRECTION_APPENDED. Each includes event ID, portfolio ID, UTC time, run/config/source hashes, policy version, payload, and previous-event hash. Never edit or delete an event through the application.
Points cannot go below zero, exceed fixed experiment limits, or convert to currency. A paper position contains source ID, direction, synthetic units, assumed fill value, latest descriptive mark, and resolution status. Unresolved marks are scenarios and do not count as final outcomes.
The overview shows starting points, unused points, points tied in unresolved cases, resolved change, maximum synthetic drawdown, concentration by topic, stale marks, abstentions, and data-quality failures. Display denominators and assumptions beside every metric. Avoid green/red celebration language that gamifies a financial result.
Reconciliation replays all events, verifies the hash chain, and compares derived state with any cached projection. If they differ, the report stops and names the first mismatch. A correction references the erroneous event and adds the compensating effect; history remains visible.
Create two views: an operator ledger showing event-level detail and a learner dashboard showing aggregated fictional points. Both display portfolio schema, policy version, last reconciled event, and data-through time. A scenario mark must never be labelled gain, income, cash, or available balance. Exporting CSV includes the same safety metadata so meaning is not lost outside the interface.
Test resolution revisions explicitly. When an authoritative outcome source changes or a prior mapping is found wrong, append a dispute event, freeze derived headline metrics, perform human review, then append a new version. The report shows both histories and the reason; it never rewrites the original curve.
Archive reconciliation evidence with every published dashboard.
🇵🇰 Pakistan Angle
Use this artifact to show accounting-style event sourcing and reporting. It is not a wallet, savings simulator, or earnings projection. No screen asks for bank, CNIC, phone, Easypaisa, JazzCash, or exchange details.
Hands-On Exercise
Create a 1,000-point fictional portfolio, append three fills, resolve one, void one, and correct one metadata error. Replay into an overview and deliberately corrupt a cached projection. Prove reconciliation fails closed and that original history remains readable.
Completion Rubric
- Portfolio state derives from append-only events.
- Points have fixed experimental limits and no money mapping.
- Unresolved marks stay separate from resolved outcomes.
- Corrections append references instead of editing history.
- Hash-chain and projection reconciliation fail closed.
Sources
Key takeaway: A paper portfolio is trustworthy when every fictional point can be replayed from immutable, reconciled, versioned, independently auditable events.