How to Commission a Test Fit That Answers the Leasing Question is a question that sits at the intersection of facility planning, lease economics and transaction timing — and most occupier teams answer it too late, too narrowly, or with the wrong brief in hand.
Why the Test Fit Exists in the Leasing Process
A test fit is not a design document. It is a decision tool. Its sole purpose is to determine whether a specific floor plate, in a specific building, can accommodate a defined headcount and operating model at a cost that the business can justify. When teams lose sight of that purpose, they commission drawings that answer the wrong question entirely.
The leasing question is almost never purely aesthetic. It is usually some combination of: can the floor hold the people, does the layout support the workflow, what will the tenant improvement cost to get there, and does the resulting effective rent still beat the alternatives? A test fit that cannot answer those four questions is incomplete, regardless of how polished the rendering looks.
Understanding the connection between a test fit and lease NPV analysis is what separates occupier advisers from space planners. The drawing is an input, not an output. When the test fit result changes the density assumption or shifts the TI cost projection, the entire economic model shifts with it.
Defining the Brief Before Engaging Any Architect
The brief is the most consequential document in the test fit process, and most occupier teams write it too thin. A four-line email to a space planner asking for "a layout for 200 people" will produce a drawing that does not answer the leasing question. A proper brief specifies headcount, seat type mix, adjacency requirements, operational constraints, and growth assumptions over the lease term.
Seat type mix deserves particular attention. The ratio of assigned desks, hoteling stations, focus rooms, collaboration areas and support spaces directly determines whether a floor plate is efficient or wasteful for a given occupier. If the brief says 200 seats but does not specify that 30 percent are unassigned and 20 percent of the floor must carry enclosed offices, the space planner has no basis for an accurate density calculation.
Growth assumptions are equally important and are almost always underspecified. If the lease term is ten years and the company expects headcount to grow by 25 percent over that period, the test fit must demonstrate that the floor plate can absorb the growth without a redesign. That condition belongs in the brief, stated as a numerical range, not left to the space planner's imagination.
The brief should also identify any operational non-negotiables: server rooms, trading floors, lab benches, controlled-access zones, or noise-sensitive areas that require acoustic separation. These are hard constraints that immediately affect usable density, and they frequently disqualify floors that look right on paper but fail on closer inspection.
Selecting the Right Space Planner for the Assignment
Not every architect or interior designer is the right person to commission for a leasing test fit. The skills required are specific: fluency with commercial floor plate conventions, the ability to test multiple layout variants quickly, and the professional judgment to flag when a floor plate cannot work rather than force a solution that technically fits but practically fails.
Firms that specialize in corporate interiors at scale typically have the density benchmarks and block plan templates to turn around a credible test fit in five to seven business days. Boutique residential or hospitality designers do not have those tools in their workflow, and the result is usually a drawing that takes longer and answers fewer of the questions the occupier actually needs resolved.
The fee structure matters for the commissioning decision. Test fits for shortlisted properties during active leasing negotiations are almost always funded by the landlord, either through a complimentary test fit provision in the LOI or through the building's standard leasing package. When the occupier is commissioning independent test fits to compare multiple properties on equal analytical terms, the occupier pays and owns the resulting drawings. That distinction affects how the brief is written and how much commercial pressure the space planner is under.
Regardless of who pays, the occupier's adviser should control the brief. When the landlord commissions the test fit on the occupier's behalf using the landlord's preferred architect, there is an inherent tension: the architect is engaged to make the floor work, not to identify when it does not. An occupier-controlled brief removes that bias from the process.
Setting the Density Target and Usable Area Assumptions
Density targets are stated as rentable square feet per person, usable square feet per person, or seats per 1,000 rentable square feet — and the convention used in the brief must match the convention used in the lease and the financial model. Mixing rentable and usable figures without an explicit conversion using the building's load factor is one of the most common sources of error in test fit analysis.
A hypothetical example illustrates the problem. Suppose a building quotes space at 20,000 rentable square feet with a 20 percent load factor, yielding 16,000 usable square feet. If the occupier's target is 200 usable square feet per person, the floor supports 80 people. If someone mistakenly applies that target to the rentable figure, they conclude the floor supports 100 people. That 20-person gap, applied to a ten-year lease at a hypothetical market rent, represents a material financial error.
The load factor — sometimes called the add-on factor or the common area factor — should be verified against the lease's measurement method, which is typically based on a recognized measurement standard. Quoted load factors from marketing materials are not always the same as the load factor embedded in the lease rent calculations. Requesting the actual measured data from the landlord is a reasonable step before finalizing the density assumption in the brief.
Usable area assumptions must also account for column positions, mechanical penetrations, floor plate irregularities and any areas excluded from the demised premises. A rectangular floor plate at 20,000 rentable square feet behaves very differently from an irregular floor plate at the same size. The brief should instruct the space planner to flag any features that reduce effective planning area beyond what the gross dimensions suggest.
Structuring the Test Fit to Produce Comparable Outputs
When a test fit is being commissioned across multiple candidate buildings during a site selection process, the outputs must be structured for direct comparison. That means using the same program brief on every property, requesting the same drawing deliverables from every space planner, and capturing the same metrics from every result.
The minimum useful deliverable set for a leasing test fit is a block plan showing primary use zones, an occupied seat count, an efficiency ratio expressed as rentable square feet per occupied seat, a circulation percentage, and a flag for any program elements the floor plate cannot accommodate. Without that consistent output set, the occupier is comparing an apples-to-oranges drawing set rather than a structured evaluation.
Some advisers add a TI cost trigger to the deliverable: the space planner notes which design decisions in the test fit are standard market practice and which represent premium choices that will increase the tenant improvement cost. That commentary turns a visual document into a cost signal, which feeds directly into the effective rent calculation.
The block plan format matters. A test fit produced as a rendered perspective is visually engaging but analytically weak — it is difficult to extract seat counts, verify circulation widths or measure zone areas from a rendered image. Requesting AutoCAD or PDF deliverables with area annotations preserves the ability to audit the drawings against the brief and the lease measurements.
Reading a Test Fit Drawing as an Adviser, Not a Designer
An occupier adviser reviewing a test fit does not need to be an interior designer, but needs to know exactly what to look for. The first check is whether the seat count on the drawing matches the brief. It is surprisingly common to receive a test fit that answers a different headcount than the one specified — usually because the architect applied their own density benchmark rather than the one in the brief.
The second check is circulation. Building codes in most jurisdictions set minimum egress widths, but the operational question is whether the circulation pattern on the drawing allows people to move through the space without creating bottlenecks. A test fit that achieves a high seat count by reducing internal circulation paths to the absolute minimum may technically comply with the brief while creating a workspace that does not function in practice.
The third check is support space allocation. Meeting rooms, focus rooms, phone booths, and wellness spaces are frequently squeezed when the primary goal is maximizing seat count. If the program brief specified a ratio of meeting seats to workstations, verify that ratio against what the drawing actually delivers. A shortfall in meeting space is a hidden cost: occupiers typically address it after move-in by leasing additional conference center space or converting workstations.
The fourth check is the TI narrative. Any floor plate feature that requires structural work, electrical upgrades, or plumbing relocation to accommodate the program should be flagged in the adviser's review note, even if the space planner did not raise it. HVAC capacity for high-density occupancy, supplemental cooling for server rooms, and electrical panel capacity for a training center are common examples where the test fit drawing looks feasible but the building infrastructure does not support it without significant capital.
Connecting the Test Fit to Effective Rent Analysis
The test fit result is an input to the financial model, not a standalone deliverable. The connection runs through three variables: occupied seats, TI cost, and lease term. Once the test fit confirms the floor can support the target seat count, those numbers feed the financial comparison that determines whether the building makes economic sense.
Effective rent — the net present value of total occupancy cost per occupied seat per year, expressed over the lease term — is the metric that allows different lease structures to be compared on equal terms. A building with higher face rent but a larger TI allowance may produce a lower effective rent than a building with lower face rent and a minimal allowance. The test fit is the mechanism that validates whether the seat count assumption in that calculation is real or theoretical.
Lease NPV calculations add time value of money to the effective rent analysis. When the occupier is comparing an early lease execution against waiting for a larger floor plate at a competing property, the present value of the rent stream over the respective lease terms becomes the relevant comparison. That calculation requires a confirmed seat count from a test fit — otherwise the per-seat normalization is built on an estimate that may be wrong by 15 to 20 percent.
The financial model should be rebuilt after every material test fit result that changes a key assumption. If the initial brief assumed 200 seats and the test fit confirms only 175 fit the floor plate at the required quality standard, the model should be rerun at 175 before the occupier makes any leasing decision. Running it at 200 and noting the discrepancy in a footnote is not sufficient.
Commissioning Test Fits in Parallel Across the Shortlist
One of the most effective tactical decisions an occupier adviser can make is commissioning test fits for all shortlisted properties simultaneously rather than sequentially. Sequential test fits create a moving target: by the time the third property's drawing arrives, market conditions or the client's program requirements may have shifted, making early drawings obsolete.
Parallel commissioning requires more coordination upfront — issuing the same brief to multiple space planners, managing competing access requests with multiple landlords, and synchronizing delivery timelines — but it produces a decision-ready comparison set within a single window. For a typical shortlist of three to five properties, a parallel test fit program run with a consistent two-week delivery deadline gives the occupier team a simultaneous comparison rather than a sequential queue.
Landlord cooperation is a practical constraint. Some buildings have exclusive test fit architects who do not accept outside briefs, meaning the occupier must negotiate the brief rather than impose it. In those situations, the adviser should provide the brief to the landlord in writing and request confirmation that the space planner will follow it. Any deviations from the brief in the resulting drawing should be treated as a gap in the analysis, not a creative interpretation.
Negotiating Test Fit Commitments in the LOI
A letter of intent is the natural place to formalize the test fit commitment before the lease is drafted. Standard market language gives the occupier the right to commission a test fit at the landlord's expense during the due diligence period. What is less standard, but worth negotiating, is a provision that ties the TI allowance to the actual cost of delivering the test fit program rather than a fixed dollar amount per square foot.
Fixed TI allowances stated in LOI terms reflect a market average. When the test fit reveals that the specific occupier program requires above-average MEP upgrades, the fixed allowance becomes a source of financial risk that the occupier absorbs through higher above-standard TI costs. Negotiating a test fit completion and pricing process into the LOI — with a right to renegotiate the allowance if costs exceed a specified threshold — protects the occupier's economics before the lease is signed.
The timing of the test fit completion relative to the LOI execution is a leverage point. A landlord who has accepted an LOI from an occupier has limited motivation to rush the test fit. Specifying a completion date in the LOI, with a consequence if the date is missed, keeps the process on track and prevents the test fit from becoming a source of negotiating delay that benefits the landlord.
Documenting and Carrying the Test Fit Through Transactions
A test fit drawing produced during the LOI phase should not disappear into an email archive once the lease is signed. It is the design intent document that the tenant improvement construction documents must ultimately deliver, and discrepancies between the test fit program and the final CD set are a frequent source of post-occupancy complaints.
Documenting the test fit as a formal project milestone — with version control, a written summary of key metrics, and a record of any brief deviations — creates a traceable line from the leasing decision to the delivered space. When disputes arise about whether the finished space meets the original program, the documented test fit is the reference point.
Facility Planning Beyond the Initial Test Fit
The first test fit answers whether a floor plate works at a point in time. Facility planning for an occupier who signs a ten-year lease requires thinking through how the space performs across the entire lease horizon. A floor that works at 200 seats today may need to be reconfigured for 250 seats in year five — and that reconfiguration cost belongs in the initial financial analysis.
Commissioning a phased test fit — a primary layout for day-one occupancy and an alternative layout for a projected growth scenario — adds meaningful depth to the facility planning analysis without doubling the cost. Most experienced space planners can produce both scenarios from the same brief if the growth parameters are clearly stated.
Tracking the commitments that flow from the test fit — phased TI schedules, landlord work completion obligations, critical dates tied to design delivery — is a separate operational discipline that extends through the lease term. The decisions made during the test fit commissioning process become lease obligations that require ongoing oversight.
Evaluating the Final Test Fit Against the Leasing Question
The final step in the methodology is the simplest to describe and the hardest to execute with discipline: return to the original leasing question and test whether the test fit has answered it. Can the floor hold the people? Does the layout support the workflow? What will the TI cost to execute it? Does the resulting effective rent beat the alternatives?
If all four questions have documented, numerical answers supported by a completed test fit drawing, a confirmed TI cost estimate and a financial comparison run on the confirmed seat count, the occupier has the information needed to make a leasing decision. If any of the four questions remains unanswered or rests on an assumption rather than a verified figure, the test fit process is not complete.
Advisers who build this four-question checklist into their standard process stop leasing decisions from advancing on incomplete information. The checklist also creates a natural handoff point: once the four questions are answered, the economic analysis and the leasing recommendation can be presented to the client with a clear line from the data to the decision.
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