--- title: "21220 — Technical Specification" url: https://australianproperty.network/apn-codex/series-20000/series-21000/series-21200/21220-inflation/technical-specification/ date: 2026-07-03 modified: 2026-10-11 lang: en author: "Nicklas Clark" description: "APN Codex · Inflation (21220)Technical Specification Inflation (21220) — Technical Specification Published 3 July 2026 · Updated 5 September 2026 · Basis: certified parameters This page sets out the full..." word_count: 515 --- # 21220 — Technical Specification APN Codex · Inflation (21220)Technical Specification ### Inflation (21220) — Technical Specification Published 3 July 2026 · Updated 5 September 2026 · Basis: certified parameters This page sets out the full methodology behind Inflation (21220): vector construction, baseline parameters, composite aggregation, and the certification record. Where any prior research document conflicts with the figures below, the certified figures on this page are authoritative. #### Vector architecture | Vector | Series | Source | μ | σ | N | Weight | | ------ | ------ | ------ | --- | --- | --- | ------ | | Headline CPI Index | 28 · ABS 6401.0 | ABS (quarterly) | 80.7828 | 9.2647 | 60 | 0.20 | | Housing CPI Index (primary) | 29 · ABS 6401.0 Housing Group | ABS (quarterly) | 77.5118 | 10.4236 | 60 | 0.20 | | PPI House Construction | 30 · ABS 6427.0, Tables 17–18 | ABS (quarterly) | 127.8183 | 25.4325 | 60 | 0.20 | | Consumer Inflation Expectations | 31 · RBA G3 | RBA (quarterly) | 4.7271 | 0.6168 | 20 | 0.20 | | Trimmed Mean CPI Index | 61 · ABS 6401.0, Appendix 1a (A3604509L) | ABS (quarterly, added 5 Sep 2026) | 116.3648 | 12.7956 | 60 | 0.20 | All five vectors are Tier-1 sovereign sources; no commercial data dependency exists in the node. Series 28–30 and 61 share the full baseline window (March 2011 – December 2025, N = 60); series 31 is a short-history series (March 2021 – December 2025, N = 20, below the platform's minimum observation count), disclosed on every certification of this node. The monthly trimmed-mean annual-change series published alongside series 61 from April 2025 is used for current-read citation and charting only; it is not a composite input, as its history cannot support a baseline. #### Composite construction Certified Aggregation Method Zv,t = (Xv,t − μv) / σv  →  Z21220,t = Σ wv Zv,t over vectors present, w = 0.20 each The certified node reading is the five-vector composite. The Housing CPI series is designated the node's primary vector for interpretive purposes — its vector-level Z-score is reported alongside the composite, not in place of it. Missing observations are carried as NIL RETURN, never estimated. **Methodological note:** the certified composite for this node is the equal-weighted blend of all mapped vectors — not the Housing CPI vector alone. The blend was four vectors at 0.25 each through the 2 August 2026 certification (+2.0502σ, Q2 2026) and five vectors at 0.20 each from 5 September 2026 (+2.1049σ, Q2 2026), when the Trimmed Mean CPI index was added. The change in the Q2 2026 reading is a methodology change, not a data revision. #### Certification record | Reference period | Composite Z | Coverage | Status | Note | | ---------------- | ----------- | -------- | ------ | ---- | | Q4 2025 | +1.5379σ | 4 of 4 vectors | Certified 15 Jun 2026 | First formal certification for this node | | Q1 2026 | +1.8549σ | 4 of 4 vectors | Pipeline reading — never certified | Superseded by the Q2 2026 certifications below | | Q2 2026 | +2.0502σ | 4 of 4 vectors | Certified 2 Aug 2026 | Superseded 5 Sep 2026 (fifth vector added) | | Q2 2026 | +2.1049σ | 5 of 5 vectors | Certified 5 Sep 2026 | Current — Trimmed Mean CPI index (series 61) added, weights rebalanced to 0.20 each; series 31 short-baseline disclosure carried | #### Terminal observations (as at 5 September 2026) | Vector | Dec 2025 (baseline cert.) | Dec 2025 Z | Q2 2026 (current cert.) | Q2 2026 Z | | ------ | ------------------------- | ---------- | ----------------------- | --------- | | Headline CPI Index | 100.32 | +2.1088σ | 102.31 | +2.3236σ | | Housing CPI Index (primary) | 99.95 | +2.1526σ | 103.80 | +2.5220σ | | PPI House Construction | 177.1 | +1.9377σ | 182.6 | +2.1540σ | | Consumer Inflation Expectations | 4.6976 | −0.0477σ | 5.4681 | +1.2014σ | | Trimmed Mean CPI Index | 143.7064 | +2.1368σ | 146.096 | +2.3236σ | The next scheduled data event for this node is the ABS CPI September quarter release, due late October 2026 (series 28, 29 and 61), followed by the ABS PPI release for series 30. Certified rows are frozen historical records. The APN Academy distillation suite for this node carries references A-260917-C21220.1 through A-260917-C21220.6. [Parent nodeInflation (21220) — Codex node page](https://australianproperty.network/apn-codex/series-20000/series-21000/series-21200/21220-inflation/)