Glossary · Data provenance

How to read the research outputs

Plain-English definitions, source provenance, and honest limitations for the Holland Market Research desk. This page is meant to keep the product source-first: every metric, score, forecast, and caveat should be understandable before it is used in a market discussion.

Metric glossary Data provenance Back to markets

Metric glossary

One-line definitions, computation notes, and reading rules for the core measures.

Supply

supply growth

Computed: Annualized apartment inventory / delivery growth from the source series for each metro and scenario where available.

Read it as: Positive supply growth means new competitive units are arriving; high supply without matching demand raises lease-up risk.

Demand

demand growth

Computed: Apartment demand growth from Green Street history/forecast, with public employment and migration features reserved for the long-history challenger panel.

Read it as: Demand growth is the occupancy/rent support side of the equation, not a recommendation by itself.

Balance

supply-demand balance

Computed: Demand growth minus supply growth over the same period, with frequency and source vintage retained in lineage.

Read it as: Positive balance indicates absorption is outrunning new supply; negative balance flags overbuild pressure.

Cycle

cumulative gap

Computed: Running sum of quarterly demand-minus-supply gaps from the available history window.

Read it as: Shows whether a market has accumulated undersupply or oversupply across cycles, not just in the latest quarter.

Score

opportunity score

Computed: Weighted blend of four pillars: undersupply, forward demand, inverse supply threat, and valuation, using the documented Phase 2c weights.

Read it as: A research prioritization tool for comparison, not a public ranking or investment instruction.

Pillars

opportunity score pillars

Computed: Undersupply captures balance/cumulative gap; forward demand captures scenario demand; supply threat penalizes future deliveries; valuation captures cap-rate / pricing context.

Read it as: Use pillar disagreement to see why a market ranks where it does instead of relying on a single blended number.

Scenarios

forecast scenarios

Computed: Green Street 2026Q1 scenario paths: Baseline, stronger growth variants, moderate recession, and protracted slump.

Read it as: Scenario lines show sensitivity to macro paths; they are not new vintages or realized outcomes.

Challenger

challenger quantile fan

Computed: Walk-forward challenger model distribution with p10 / p50 / p90 bands, currently cross-checking Green Street rent growth rather than replacing it.

Read it as: Use it as disagreement evidence and uncertainty framing; challenger = cross-check, not ground truth.

Data provenance

Sources actually used today. License field intentionally distinguishes free-public from licensed/current private inputs.

Source	What it provides	Geography	Earliest date	Frequency	License	Role	Known limitations
Green Street forecast	Apartment supply, demand, rent growth scenarios, fundamentals and valuation inputs	Covered apartment markets	Varies by metric; current site uses one 2026Q1 vintage	Quarterly / scenario	current source delivery	primary	Green Street forecast = single 2026Q1 vintage; accuracy is unscoreable until later vintages/realizations exist.
Green Street supply / fundamentals / permits files	Supply growth, permits, cap rates, CPPI, market fundamentals	Metro / Green Street market	Source-dependent	Quarterly / annual source-dependent	current source delivery	primary	Coverage differs by market and metric; missing or sparse coverage is flagged rather than silently filled.
CM Alert CMBS + CRE CLO databases	Securitized debt issuance and multifamily share context	National only	Source-dependent	Quarterly aggregate	current source delivery	context	debt data = national-only (never metro); deal files are not joined to individual markets.
FRED / Census BPS / BLS / HUD / ACS / IRS migration	Planned free-public long-history permits, employment, wages, FMR, income, population, household formation, migration features	Metro / CBSA / county reconciled through market_crosswalk.csv	Target late-1980s to early-1990s where available	Monthly / quarterly / annual native frequencies	free-public	planned primary/context	Phase 4b only; annual series are never fabricated to monthly, and unmatched metros must be reported.
Zillow	ZORI multifamily and ZHVI recent rent/value breadth	Metro / Zillow geography	ZORI ~2015; ZHVI ~2000	Monthly	free-public CSV	validation	Zillow/Apartment List = shallow (2015/2017+); useful for validation and recent breadth, not deep cycle training.
Apartment List	Recent rent and vacancy measures	Market / metro	~2017	Monthly	free-public CSV	validation	Shallow history only; not a substitute for licensed apartment-specific absorption history.
Challenger model	Rent-growth p10 / p50 / p90 fan and disagreement checks	Covered markets with feature history	Feature-window dependent	Quarterly model panel	internal model output	cross-check	challenger = cross-check, not ground truth; with more true apartment cycles the current AR(4) verdict could flip.

Reserved / future data

Not pulled, not scraped, and not assumed. These are future accuracy upgrades only if team licenses are confirmed.

Current outputs are built on free public data plus the current Green Street delivery. These licensed feeds, if secured, would raise fidelity in the specific areas below; until then, they remain reserved and outside the pipeline.

CoStar

Status: not-yet-licensed; do not scrape or ingest

Unit-level supply, construction, leasing, absorption, and rent evidence across broader apartment coverage.

Deeper apartment-specific history could add cycles and improve challenger training.
Metro breadth could expand the map/ranking from 40 to 100+ markets.
Measured absorption could replace demand proxies in the balance read.

RealPage

Status: not-yet-licensed; do not scrape or ingest

Apartment operating fundamentals, effective rents, occupancy, supply and absorption depth by market/submarket.

True effective rent and absorption history would tighten supply-demand balance.
More cycles may change the challenger model selection and AR(4) verdict.
Submarket-level detail would improve development-screen specificity.

Moody's CRE (REIS)

Status: not-yet-licensed; do not scrape or ingest

Long apartment rent, vacancy, inventory, and market fundamentals history, often back to the 1990s.

History to the 1990s would add recession/recovery cycles.
Coverage beyond the current Top 40 would support a fuller national market map.
Apartment-specific vacancy and absorption could replace coarser public proxies.