SSM-Audit – Implementation Guide (2.13–2.15)

time, unit, kpi, m, a, band, U, W, knobs_hash, build_id, stamp
# U,W optional (expose if you want verifiable rollups)
# stamp optional (enable if provenance needed)

# Band from lane (cell formula)
=IFS(a>=0.75,"A++", a>=0.50,"A+", a>=0.25,"A0", a>=0.10,"A-", TRUE,"A--")

# Hysteresis (requires a_prev and band_prev)
=LET(delta_a, a - a_prev,
     cand, IFS(a>=0.75,"A++", a>=0.50,"A+", a>=0.25,"A0", a>=0.10,"A-", TRUE,"A--"),
     IF( (cand>band_prev)*(delta_a>=0.05) + (cand<band_prev)*(delta_a<=-0.05),
         cand, band_prev))

# Calculated column BandFromA
BandFromA =
SWITCH(TRUE(),
    a >= 0.75, "A++",
    a >= 0.50, "A+",
    a >= 0.25, "A0",
    a >= 0.10, "A-",
    "A--"
)

# Measures for weekly counts (illustrative)
App_Count := COUNTROWS( FILTER(Fact, Fact[BandFromA] = "A++") )
Ap_Count := COUNTROWS( FILTER(Fact, Fact[BandFromA] = "A+") )
...

POST /lane
Content-Type: application/json

{
  "kpi_id": "AR_collected_issued",
  "date": "2025-10-21",
  "m": 0.9631,
  "a": 0.6123,
  "band": "A+",
  "knobs_hash": "9d5c...e2",
  "build_id": "pilotW1",            # optional
  "stamp": "SSMCLOCK1|..."          # optional
}

# Idempotency key (recommended):
#   Idempotency-Key: kpi_id|date|knobs_hash
# Server stores/replaces by (kpi_id,date) if knobs_hash matches

revenue
daily_rev
days_reduced_in_DSO
refund_rate_baseline
refund_rate_after
gross_sales
MAPE_baseline
MAPE_after
k_cash

Savings_AR  := days_reduced_in_DSO * daily_rev
Savings_ref := (refund_rate_baseline - refund_rate_after) * gross_sales
Savings_fc  := (MAPE_baseline - MAPE_after) * revenue * k_cash
Savings_total := Savings_AR + Savings_ref + Savings_fc

# k_cash translates forecast accuracy into cash impact (org-specific).
# All rates as decimals; units consistent (currency/day where applicable).
# Use rolling baselines so improvements are attributable to lane-driven actions.

Data: stamped CSVs, manifest (ASCII), knobs_hash, CI PASS/WARN/FAIL report
Plots: weekly a-trends with band shading; SDI if used
Notes: 3–5 "caught-early" examples (band slide -> action -> outcome)
Review: quarterly knobs review; update manifest; recompute conformance_checksum

[ ] C1 Clamp safety (-1 < a < +1 after clamp)
[ ] C2 Collapse parity (phi((m,a)) = m everywhere)
[ ] C3 Band parity (band_from_a)
[ ] C4–C6 Order/ratio/rollup parity (within epsilon)
[ ] C7 Deterministic export (replay identical)
[ ] C8 Knobs fingerprint (hash flips on knob change)
[ ] C9–C10 Stamps/anchors (if enabled)
[ ] C11 Hysteresis sanity (promote/demote rules)
[ ] Privacy posture (no PII in lanes/stamps)