Published method
How the HCTI is calculated
The HCTI normalizes seven public series to January 2026 = 100, builds a fixed material basket, then combines material and construction-wage movement at equal top-level weights.
Formula
HCTI = 0.50 × material basket + 0.50 × construction wage index
Material basket = 0.50 × finished construction inputs + 0.10 each × lumber, copper wire, cement, gypsum, and steel
Each component index equals 100 × current observation ÷ January 2026 observation. Fixed weights make every monthly result reproducible and prevent recent volatility from changing the basket itself.
Published weights
| Component | Series | HCTI weight | Automated validation |
|---|---|---|---|
| Net inputs to construction industries, goods | WPUIP2300001 | 25% | Validated on every scheduled run |
| Lumber | WPS081 | 5% | Validated on every scheduled run |
| Copper wire and cable | WPU10260314 | 5% | Validated on every scheduled run |
| Cement manufacturing | PCU327310327310 | 5% | Validated on every scheduled run |
| Gypsum products | WPU137 | 5% | Validated on every scheduled run |
| Steel mill products | WPU1017 | 5% | Validated on every scheduled run |
| Construction average hourly wage | CES2000000003 | 50% | Validated on every scheduled run |
Why these weights are fixed
The 50/50 top-level split is an index policy, not a claim that every renovation is half materials and half labour. Project calculators apply job-specific, source-backed quantities and hours. The HCTI only moves those dated inputs between source updates.
The broad finished-inputs series carries half of the material basket. Five dedicated series divide the remaining half equally so material shocks remain visible without allowing one commodity to control the full index.
Publication gates and degraded mode
- Every external request retries three times with exponential backoff and an independent official fallback where one is available.
- A non-critical missing component may publish only while unavailable weight remains at or below 33.3%; remaining components are reweighted proportionally and the snapshot names the omission.
- A critical failure or unavailable weight above that limit retains the last good period and switches freshness text automatically.
- Observations older than 75 days and absolute month-over-month movement above 3 points block a new period.
- An existing monthly snapshot cannot be overwritten with different contents.
Limitations
The national HCTI measures input movement, not retail contractor bids. It excludes company overhead, margin, job complexity, financing, and local scarcity. Metro multipliers are built separately from OEWS wages, BEA regional price parities, permit data, and the HUD ZIP-to-CBSA crosswalk.