Calculation catalog › Insights
Insight impact lifetime tax delta
Estimated change in lifetime taxes from an insight action.
Field: lifetimeTaxDelta Unit: US dollars Basis: nominal dollars Computed by: Engine Status: Complete chain
Appears in: insights (InsightCardView "Lifetime tax delta" after Preview impact)
Calculation records
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Insight impact: ending after-tax estate and lifetime tax deltas Formula record, justified by derivation
Purpose: What an insight's modeled action does to the estate and to lifetime taxes, as candidate minus baseline.
Statement: decisions/evaluateCandidate.ts#evaluateCandidate prices the candidate on its own full year-by-year projection and subtracts the shared baseline in the same direction for both fields: endingAfterTaxEstateDelta = candidateSummary.endingAfterTaxEstate - baselineSummary.endingAfterTaxEstate, and lifetimeTaxDelta = candidateSummary.lifetimeTaxesAndPenalties - baselineSummary.lifetimeTaxesAndPenalties. The estate field's comment states that order outright and the lifetime-tax field defines a negative value as savings, which is the same convention: an estate improvement is positive and a tax saving is negative. Units: nominal dollars, not today's: the estate delta is in dollars of the plan's last year (both runs end in that year), and the lifetime tax delta sums each year's own dollars. Rounding: none.
Formula:
estateDelta = E_candidate - E_baseline; taxDelta = T_candidate - T_baseline-
E: Ending after-tax estate of a run's summary (unit: usd) (domain: finite) -
T: Lifetime taxes and penalties of a run's summary (unit: usd) (domain: nonnegative)
Timing: once per evaluated candidate, against the context's single shared baseline
Rounding: none
Limits:
- Beyond the worksheet's inputs the evidence plan fixes two real one-year projections that land on the worksheet's four summary figures exactly: a 1963-born single filer (over 59.5 so no early-distribution rule, under 65 so no Medicare premium) with one $1,800,000 traditional account, a flat 25% tax double, heirTaxRatePct 50, zero return and zero inflation, and base spending of $600,000 in the baseline against $555,000 in the candidate scenario. At a flat rate r the withdrawal funding spending S is S / (1 - r) and the tax is r x that, and the estate is the remaining balance net of the heir rate
- The flat calculator is a test double, never the shipped stack: it exists so the test can name exact dollars without recomputing federal law, and it must not be read as a tax result
- Both deltas are differences of SUMMARIES, so they inherit every convention of summarizeProjection: the heir-tax haircut, charity carve-outs, and the fact that property, debts and ladder face ride through net worth without per-account estate rows
- The irmaa-tier-edge Insight writes its annual premium cliff into endingAfterTaxEstateDelta as an avoidance signal rather than an estate change; that exception belongs to that Insight’s own record and the evidence here does not exercise it
Provenance: derived by
codex, implemented byclaude.Independent review:
grokGates (6 of 6 pass): fixture registers a test: pass; pins resolve: pass; families exist: pass; worksheet exists: pass; mutation receipt exists: pass; provenance independent: pass
Worksheet: insight-impact-estate-and-lifetime-tax-deltas.md Mutation receipt: insight-impact-estate-and-lifetime-tax-deltas.mutation.md
Evidence tests: evaluateCandidate.evidence.test.ts
Implemented in: evaluateCandidate.ts; types.ts; insightsAdapter.ts
Is the number of: insight-impact-ending-after-tax-estate-delta, insight-impact-lifetime-tax-delta
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Engine source: engine/src/insights/types.ts
(InsightImpact.lifetimeTaxDelta)
The evidence links on this page (each record's worksheet, mutation receipt, evidence tests
and implementation, and the source links) are pinned to engine commit
2624dbdba9fd, committed 2026-10-11.
The live calculation index and
output-family census links point at the repository's main
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