/TAG

#time-series

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Prevent lookahead in historical backtests Limit each signal to information available at its decision time.
Build latest snapshots with calendar change rates Calculate monthly and annual changes using the newest observation within a seven-day calendar tolerance.
Scope Reconciliation Checks by Grain and Window Validate signed summary totals only within matching scope; keep that check separate from detail-row verification.
Preserve Observation Meaning and Vintages Keep measurement identity, missingness, availability, and revisions explicit.
Correct Calendar-Based Year-Over-Year Specs Replace row-offset comparisons with the specified calendar tolerance rule before implementation.
Build an Aligned Two-Tier Monthly Dataset Preserve unmatched tiers while aligning monthly series and merging them at a stable grain.
Calculate ratios only on matching dates Prevent a lagging series from silently producing a ratio between different observation dates.
Make annualization frequency explicit Require periods per year and inspect existing library behavior before annualizing a statistic.
Compare Cross-Domain History with Matched Periods Compare each series against its own equivalent period while preserving geography and coverage.