# Benchmarking data against the market: absorption, cap rate, and rent indices
Your leasing team reports the office building at 90% occupancy and rents up 4% year over year. CoStar's submarket index shows average occupancy at 82% and rents flat. Someone is wrong, or something is genuinely unusual about your asset. Either way, you cannot know which until you benchmark your internal data against external, independently collected market data. This is the discipline this lesson covers: what to compare, against what sources, and how to tell noise from signal.
A property's own numbers are self-referential. Occupancy, asking rent, days-on-market: these describe your building, not the market. Without an external anchor, you cannot tell if your performance is:
Benchmarking closes that gap by placing your numbers next to a market-wide reference built from many properties.
The National Council of Real Estate Investment Fiduciaries (NCREIF) runs the Property Index (NPI), a US database of institutionally owned, unlevered commercial properties, updated quarterly. It reports total returns broken into income and appreciation components, by property type (office, industrial, retail, apartment) and region. Because contributing funds must meet reporting standards, NPI is the closest thing US institutional real estate has to an audited benchmark. Free summary data: ncreif.org.
Limitation: NPI reflects only unlevered, institutionally held stabilized assets. It excludes most private, leveraged, or opportunistic deals, and skews toward large core markets.
CoStar is the dominant US commercial real estate data provider, tracking leasing comps, asking and effective rents, vacancy, and under-construction pipelinepipelineAll active sales opportunities across the stages of the sales process, together with their combined potential value and probability of closing.View full definition → down to the submarket level. It is the most-cited source for "market rent" in US broker and appraisal work. Europe has fragmented equivalents: MSCI Real Capital Analytics for transaction data, PMA and CBRE/JLL/Savills research desks for rent and vacancy series by city.
Absorption (a data metric, not a financial ratio) measures the net change in occupied square footage over a period. Positive net absorption means more space got leased than vacated. Trackers from CoStar, JLL, and Cushman & Wakefield publish this quarterly by market and property type, it is the primary leading indicator of supply-demand balance before rents move.
The capitalization rate (net operating income divided by property value) is a pricing metric, but the data question here is sourcing: where does the "market cap rate" you compare against actually come from? Key survey sources:
These three methods (transacted, surveyed, broker-estimated) can diverge meaningfully. As of early 2025 estimates, US CBD office cap rates were widely cited in the 7 to 9% range while stabilized multifamily sat closer to 5 to 5.5%, but treat any single figure as directional, not a hard fact, since methodology drives the number as much as the market does.
Say your industrial property's internal rent roll shows average net rent of $8.50/sq ft. CoStar's submarket index shows average asking rent of $7.20/sq ft for comparable Class A industrial.
Gap = ($8.50 − $7.20) / $7.20 = 18% premium to market.
Next step is not to celebrate, it's to investigate the gap:
If the premium survives these checks, you likely have a genuine outperforming asset. If not, you've caught a data qualitydata qualityThe degree to which data is fit for purpose: accurate, complete, consistent, timely, valid and unique. Poor quality data undermines analytics, reporting and AI.View full definition → problem before it fed into a valuation or investment memo.
Benchmarking is only as good as the inputs on both sides. Run these checks first:
1. Definitional alignment: does "vacancy" mean physical vacancy or economic vacancy (including free rent periods)? NCREIF, CoStar, and your property manager may define it differently.
2. Timing lag: NPI is quarterly and reported with a lag; CoStar updates more continuously but revises historical periods as new leases are recorded. Compare same-vintage data, not your Q4 actuals against a stale Q2 index.
3. Sample size: a submarket index built on 5 comparable buildings is noisier than one built on 50. CoStar and RCA both let you check underlying sample counts, always do.
4. Currency and geography consistency (Europe): a Paris CBD office yield is not comparable to a secondary French regional city; benchmarks must match geographic granularity.
A practical internal control many asset managers use:
IF |internal_metric - benchmark_metric| / benchmark_metric > 15%
THEN flag for manual review before reporting to LPs or lendersThis kind of variance threshold turns benchmarking from a one-off analysis into a repeatable data governancedata governanceData governance is the set of policies, roles, and processes that ensure data is accurate, secure, well-defined, and used responsibly across an organization.View full definition → control, catching both data errors and genuinely newsworthy outperformance.
Knowledge check
1. A leasing team reports occupancy well above the submarket average. Why is this internal figure alone insufficient to conclude the asset is outperforming the market?
2. What is the primary reason NCREIF's Property Index (NPI) is considered a strong institutional benchmark despite its limitations?
3. An asset shows rents up 4% year-over-year while the submarket rent index is flat. What is the most appropriate next step before concluding the asset is genuinely outperforming?
4. Select ALL correct answers about reasons a property's internal performance metrics might diverge from market benchmarks.
Select all the correct answers.
5. Select ALL correct answers about limitations of the NCREIF Property Index (NPI) as a benchmark.
Select all the correct answers.
| Question | Best benchmark source |
|---|---|
| Is my building's total return in line with institutional peers? | NCREIF NPI |
| Is my asking rent competitive? | CoStar / JLL / CBRE rent index |
| Is demand in this submarket strengthening? | Net absorption trackers (CoStar, C&W) |
| Is my exit cap rate assumption realistic? | RCA transaction data (most reliable) over broker surveys |
| Is my European asset priced in line with peers? | MSCI RCA Europe, national statistical offices, PMA |
Matching the question to the source matters more than defaulting to whichever dataset your firm already has a subscription to.
🎬 [VIDEO: "Understanding Cap Rates and NOI in Commercial Real Estate" - youtube.com/results?search_query=understanding+cap+rates+noi+commercial+real+estate - a practical walkthrough of how cap rate and NOI data are actually calculated and sourced, useful before comparing against survey benchmarks]