A comparable property is useful when its transaction or offering helps explain what a tenant or buyer would choose instead of the subject. Proximity alone is not enough. A nearby building with different use rights, functionality, credit, lease term, or delivery cost can be less relevant than a more distant property competing for the same occupier.
Select comparables for a defined question: achievable rent, landlord leasing cost, sale value, lease-up time, operating expense, or physical replacement. No single set answers every question. Record what the evidence supports and what remains uncertain rather than assign a property the label comparable and reuse it everywhere.
Define the decision before searching
If the question is retail rent, identify the intended tenant category, suite size, access, visibility, parking, permitted use, co-tenancy, condition, and lease responsibility. If the question is industrial rent, investigate clear height, loading, circulation, power, yard, office finish, and usable access. Office comparison needs layout, systems, amenities, access, delivery, and actual net economics.
For investment sales, add contractual income, tenant credit, lease duration, rollover, landlord obligations, capital needs, ownership rights, and transaction circumstances. A property sold with a major vacancy or buyer-funded redevelopment is not interchangeable with a fully delivered long-term lease merely because both are called industrial.
Document the subject’s measured characteristics before selecting evidence. Otherwise an analyst can unconsciously define the property to fit the most favorable transactions. A neutral subject profile makes exclusions and adjustments easier to review.
Separate evidence types
A completed sale supports a price paid under its actual conditions. An asking price supports an owner’s current request. A signed lease supports contractual terms; an asking rent does not prove the achievable concession package or collected rent. Preserve those distinctions in every table.
Confirm source, date, transaction status, area basis, lease type, price basis, condition, and any known unusual circumstances. Public records may establish a transfer without explaining concessions, business assets, financing, portfolio allocations, or post-sale obligations. State the limitation rather than invent the missing context.
An interview can provide useful professional judgment, but label it as such and retain authorized notes. Do not attribute a precise confidential deal term to a public source that never disclosed it. Inaccessible evidence cannot be made reliable by repeating it in several secondary summaries.
Chicago reporting universes are not interchangeable
Colliers’ Q2 2026 Chicago big-box report describes a specific industrial cohort. Its evidence can inform the large-format competitive landscape, but it cannot independently establish a small-bay lease rate or turnover cost. A size label is an economically meaningful boundary when tenant operations and alternatives change. Colliers Chicago big-box industrial, Q2 2026
Use a similar discipline for downtown versus suburban office, direct versus sublease availability, and retail formats. An average may combine properties the intended tenant would never consider together. Before citing a metro series, verify the universe and explain how it connects with the subject.
CMAP’s Data Hub supplies regional planning data across the seven-county northeastern Illinois region. Its geography and information can inform location analysis, but planning boundaries are not automatically lease-market boundaries or proof of parcel eligibility. Check each dataset’s scope and metadata. CMAP Data Hub
Build a comparison grid before adjusting
An original working grid can include transaction status and date; property rights; area and measurement convention; physical utility; location and access; tenant and lease terms; condition and required work; operating expense responsibilities; concessions and capital; and source confidence. Include an exclusion reason where a property fails a critical requirement.
Start with qualitative screening. If a loading configuration cannot serve the intended truck movement, its lower rent may not be a useful substitute. If an office lease is a short-term furnished sublease, it may answer a different occupancy problem from a long-term direct lease with extensive landlord work.
Then identify economic differences that can reasonably be quantified. Avoid adding a precise adjustment percentage merely to make a table look analytical. An unsupported decimal can be less informative than an explicitly unresolved range.
A hypothetical effective-rent comparison
Assume a 5,000-square-foot suite offered at $24 per square foot annually for five years. Nominal scheduled rent is $600,000. Six months free rent costs $60,000. A $100,000 landlord allowance and $20,000 commission leave $420,000 before operating costs, financing, time value, and other obligations.
Dividing by 25,000 square-foot-years gives a simplified $16.80 per square foot annual net amount on those stated deductions. This is an original hypothetical comparison, not a Chicago market rent or a formal standardized appraisal metric. A discounted cash-flow analysis would also reflect payment dates.
Now compare another 5,000-square-foot lease at $21 for five years, with three months free rent, $40,000 allowance, and $15,000 commission. Scheduled rent is $525,000; free rent costs $26,250; the remaining amount is $443,750, or $17.75 per square foot annually under the same simplified convention. The lower face rent has the higher stated net amount.
Before drawing a conclusion, compare recoveries, operating costs, credit, possession, rent commencement, landlord scope, condition, options, and remaining term. A mathematically normalized rent is not proof that the premises or risks are equivalent.
Compare capital through actual scope
A renovated building and a building requiring major work can support different prices even with similar reported NOI. Separate recurring replacement needs, immediate defects, tenant delivery, and a value-add program. Determine which costs preserve income and which are expected to create new income.
A price-per-square-foot comparison that ignores $1,000,000 required work can misstate the cheaper alternative. Add acquisition costs, scope, leasing, carry, financing, and contingency to produce a complete basis before comparing with a delivered asset. Avoid subtracting the same funded work twice.
Lease abstract and property-condition evidence help explain the differences. A vacant warehouse with modern utility may require less landlord capital for a target tenant than a fully leased but functionally weak building approaching expiration. The marketed occupancy percentage does not resolve the comparison.
Separate income conventions before comparing cap rates
Record the income period and exact deductions used in each capitalization calculation. Seller NOI, buyer normalized NOI, lender NCF, and tax-assessment income can differ. A rate calculated on one basis cannot be applied to another without reconciliation.
OCC guidance provides primary context for documented collateral valuation and underwriting. Its purpose is not to create an automatic cap-rate adjustment table; it reinforces the need for appropriate evidence, definitions, and professional judgment. OCC CRE handbook
A sale with above-market contractual rent may show strong current income but face a later reset. A below-market lease may constrain near-term cash while offering conditional future upside. Compare the lease timeline and capital required rather than call one cap rate cheap and another expensive without explanation.
Handle thin evidence with a range
When few transactions are available, widen the evidence set deliberately and disclose the resulting limitations. Expand time, geography, size, or asset attributes one dimension at a time where possible. Explain why the additional evidence remains relevant.
Use scenario ranges rather than disguise uncertainty through a single unsupported adjustment. A property with unusual power, use restrictions, ground lease, or specialized layout may require additional methods and professional advice. The absence of a perfect comparable does not justify inventing one.
Keep competing interpretations. A broker’s rent view, a buyer’s capital estimate, and a lender’s accepted income can differ for identifiable reasons. Reconcile those differences in the investment decision rather than average them mechanically into a false consensus.
Preserve the selection and rejection record
Record why each property was included or excluded before settling on a value or rent. Excluding an unfavorable transaction requires the same evidentiary discipline as excluding a favorable one. A selection log reduces the risk of choosing only data that supports the desired purchase.
Date the analysis and update material evidence. New competing supply, a tenant relocation, changed concessions, or a revised scope can alter relevance even if the distance and building size stay the same. Comparability is a relationship to a decision at a time, not a permanent property characteristic.
The final comparison should identify supported conclusions, remaining differences, and their effect on price, capital, rent, timing, and risk. A credible comparable set helps an investor understand alternatives. It does not eliminate the work of underwriting the subject’s own leases, condition, obligations, and funding.
Separate price evidence from a buyer’s special motivation
Assume a hypothetical adjacent owner buys a small parcel to complete an assembly. Its price may reflect value available only when combined with that owner’s other land. Investigate whether an ordinary buyer of the subject could obtain the same benefit before using the transaction as straightforward evidence of standalone value.
Similarly, an owner-user can evaluate occupancy savings, business fit, and capital differently from a passive investor. A sale-leaseback involves both the property transfer and the lease negotiated with the seller. Neither transaction should be discarded automatically, but both require interpretation of the rights and economics actually exchanged.
Record known circumstances and unanswered questions beside the price. Avoid an invented adjustment for motivation when evidence is unavailable. The defensible response may be to give the transaction less weight or use it as a boundary rather than a central comparable. That judgment should be explicit and consistent with the question the comparison is intended to answer.