The Price One-Pager Build Standard

Done for you: the Price One-Pager sheet

1. What this standard covers

The one page of price evidence an agent gives a vendor, before or after an appraisal, for a residential sale: the property, the comparable sales, the range those sales support, and the agent’s own estimate. It covers how the comparables are chosen, how the range is worked out, what is flagged to the agent before the vendor sees anything, and what is kept afterwards.

What is out of scope. Setting the price. The agent’s estimate is theirs, and so is the figure they quote; this standard puts the evidence beside it and says when the two disagree. A formal valuation is out of scope too, and so is advertising: the price a buyer sees is governed by the rules in the dated block below, not by this page. Commercial, rural and industrial sales are out of scope.

Where it lives. Beside the CRM you already run, not instead of it. The page and its record can sit in a shared sheet, a folder, or a small dashboard your coding agent builds. Nothing here asks you to move your listings or your contacts.

What cannot meet it. A build with no sales source it can name. Sales remembered, read off a portal screenshot, or copied without where they came from cannot meet check 4, and a build on them can only ever be honest about that. Typing sales in from a source you can name, as the free sheet does, meets every check except the pass test, which needs sales you can trace and a record that outlives the laptop it was made on.

2. The selection rules

Write the rules down before you look at a single price. A rule chosen after the prices are on screen is a rule chosen to reach a number, and that is the page a vendor disputes. These are starting values, not the standard: the standard is that there are rules, that they are read first, and that the page prints them.

Some states set their own distance and recency for comparables. The dated block at the foot of this page says what we found and when. Where a state’s rule is stricter than yours, use theirs.

3. The records it keeps, in the shape your developer needs

Six objects. The Shown record is the one most builds leave out, because the page on screen today looks like proof until somebody edits it.

Subject                           # one, read from a record
  - address, type (house | unit | townhouse | land)
  - beds, land_sqm                 # null when the record does not hold it
  - source, read_on

Rules                             # written before any sale is read
  - max_distance_km, max_age_months, same_type
  - beds_band, land_band_pct, min_count, freshness_days

Sale                              # as the source recorded it
  - sale_ref, address, type, beds, land_sqm, distance_km
  - sold_on, price
  - price_status (verified | unverified | withheld)
  - source, read_on

Appraisal                         # the agent's own, never evidence
  - agent, estimate_low, estimate_high
  - quoted_from                    # the lowest figure they intend to quote

Version                           # one per build, never edited
  - property, version, built_at
  - comparables[] (sale_ref, price, sold_on, source, read_on)
  - listed_not_used[] (sale_ref, status)
  - excluded[] (sale_ref, rule)
  - range (low, median, high) | too_few (found, needed)
  - agent_estimate (agent, low, high)
  - flags[] (too_few | underquote | stale)
  - approved_by, approved_at, approval_reason

Shown                             # append only
  - property, version, given_to, given_on
  - the Version exactly as approved

A Shown row whose comparables differ from its Version is the defect this standard exists to make impossible. So is a range with a number in it that is not a verified sale.

4. The checks, in order

The order is the claim. The rules are read before the sales, every sale is tested against every rule before the arithmetic, the agent sees the flags before approving, and nothing reaches the vendor without an approval of that exact version. A build that works out the range first and chooses rules afterwards produces a tidy page that proves nothing.

1. The subject property comes from a record. Type, bedrooms, land size and address are read from a source, not typed from memory. A field the source does not hold is shown as unknown, never guessed.
2. The selection rules are written down before any sale is chosen. Distance, how recent, property type, and the bedroom and land size bands are read from one written rule set, and printed on the page.
3. Every comparable shown meets every stated rule. A sale outside any rule is not a comparable, however close its price is to the one the agent hoped for.
4. Each comparable carries its source and its sale date. Where the sale was recorded, when it sold, and when it was read. A sale with no source or no date is left off the page.
5. A withheld or unverified price is never part of the range. A sale whose price was withheld, or reported but not verified, may be listed so the vendor sees it exists, marked as such, and is left out of the arithmetic.
6. Too few comparables means no range, and the page says so. Below the minimum count, the page says there is not enough evidence for a range. It never widens a rule quietly to reach the count.
7. The range is worked out from the comparables and nothing else. Low is the lowest verified comparable price, high is the highest, and the middle is their median. No adjustment, no model estimate, no rounding toward a figure.
8. The agent's estimate is shown separately, labelled as theirs. It sits in its own box with the agent's name on it. It never replaces the range, is never averaged into it, and is never presented as what the evidence says.
9. A quoted price below the evidence is flagged to the agent. If the lowest figure the agent intends to quote sits below the evidence range, the agent is told before anything reaches the vendor, with the sales that sit above it.
10. Stale data is held, not shown as current. Sales read longer ago than the freshness window are read again or the page is marked stale and held. A one-pager never carries an old read under today's date.
11. The agent approves the exact version before the vendor sees it. Nothing goes to the vendor without the agent's recorded approval of that version. A change after approval is a new version and needs a new approval.
12. What was shown, and when, is recorded and never overwritten. On release, the version, every comparable with its source and dates, the range, the agent's estimate, the approval, who it went to and the date are kept. A correction is a new version.
13. It survives the builder. Someone other than the builder can explain what it does, and it runs on an account the business owns.
14. The pass test passes. A real one-pager on live sales: every comparable traces to a source record with its sale date, and the record of what was shown is retrieved unchanged later.

5. The range, and your estimate

The range is the lowest verified comparable, the highest, and the median between them. That is all. No adjustment for a renovated kitchen, no weighting toward the sale you like, no figure from a valuation model. Adjustments are judgement, and judgement belongs in the other box.

An illustration, not data: four comparables sold at $850,000, $890,000, $920,000 and $960,000. The page says the evidence runs from $850,000 to $960,000 with a middle of $905,000. If you think the property is worth $1,000,000 because of the view, that goes in your box, with your name on it, and the evidence range does not move. The vendor can see both, and can see they are different things.

Why so plain. Every number in the range can be followed back to one sale on the page, so the vendor can check it and so can anybody asking later. A smoothed or adjusted range cannot be checked by anyone who did not build it, which is the property this standard exists to remove.

6. The four flags

Flags are for the agent and never appear on the page the vendor sees. Two of them hold the page until the agent deals with them.

The underquoting flag is the one that matters most. If the lowest figure you intend to quote sits below every comparable on the page, the build tells you before anything else happens, with the sales that sit above your figure. It does not decide you are wrong: there can be a reason, and the reason is recorded with your name. What it will not do is let the page go out with the gap unremarked. The rules that make this matter differ by state, and they are in the dated block at the foot of this page.

7. What stays with a person

• ✓Your estimate and the price you quote. The build puts the evidence beside them and never changes either.
• ✓Approving each version before the vendor sees it. A change after approval is a new version, and needs a new yes.
• ✓What to do when your quote sits below the evidence: revise it, or approve it with a reason that is kept.
• ✓Writing the selection rules, before looking at the prices.
• ✓Everything said to the vendor about the price. The page is evidence, not advice.

8. Run it three ways

The standard does not care where it runs. Pick the one that matches how your office already works; the checks are the same in all three.

• With the tools you already have. The free sheet above, or the same rules in a shared spreadsheet and a folder of PDFs. You paste the sales in, build the page, approve it and file it. On Microsoft 365, the build plan sets it up as lists, a flow and a library.
• A small dashboard your coding agent builds. Hand this page to Claude Code or a similar agent and ask for a one-page tool that runs these checks against the stub. It gets the checks as data from this page, and the conformance kit tells it when the build is right.
• A long-lived bot. A routine that builds the draft the night before each appraisal in your calendar and leaves it for you to approve in the morning. It drafts and flags; it never sends.

How each of the three is set up, for any standard: running a standard anywhere.

9. Join It to Your Own System: What to Stub, and What Not to Hand-Roll

One step not to hand-roll: live recorded sales with a source a person can follow, and a record of what was shown on what date that survives a dispute. Everything else a coding agent builds against the stub in an afternoon.

provider:
  stub:       local.mock_sales
  production: none                       # scoped build, not a product

the step not to hand-roll
  - live recorded sales, each with its source and sale date
  - a record of what the vendor was shown, and when, kept
    where nobody can edit it and retrievable by property and date
  No product offers live property data to other builds. Read the
  sales from a source the agency already licenses; the record
  and the join to it are quoted as a scoped build.

stays local                          # yours, and the standard
  - the subject property and the selection rules
  - choosing the comparables and the exclusions
  - the range arithmetic and the layout
  - the four flags, and the agent's approval
  - the agent's own estimate

ports the stub exposes
  readRules, readSubject, readAppraisal, readSales, refreshSales,
  select, cite, draft, notifyAgent, hold, requestApproval,
  release, keepRecord

cannot meet the standard
  - sales with no source a person can name

A vendor selling an appraisal tool is usually selling the layout. Ask them three things: which rules chose these sales, where each sale was recorded, and where the copy of what the vendor saw will be in a year.

10. A checklist to hold any build or supplier to

Hold a DIY build or a vendor to this. If a box is empty, it is not in production.

• ✓1. The subject property comes from a record. Type, bedrooms, land size and address are read from a source, not typed from memory. A field the source does not hold is shown as unknown, never guessed.
• ✓2. The selection rules are written down before any sale is chosen. Distance, how recent, property type, and the bedroom and land size bands are read from one written rule set, and printed on the page.
• ✓3. Every comparable shown meets every stated rule. A sale outside any rule is not a comparable, however close its price is to the one the agent hoped for.
• ✓4. Each comparable carries its source and its sale date. Where the sale was recorded, when it sold, and when it was read. A sale with no source or no date is left off the page.
• ✓5. A withheld or unverified price is never part of the range. A sale whose price was withheld, or reported but not verified, may be listed so the vendor sees it exists, marked as such, and is left out of the arithmetic.
• ✓6. Too few comparables means no range, and the page says so. Below the minimum count, the page says there is not enough evidence for a range. It never widens a rule quietly to reach the count.
• ✓7. The range is worked out from the comparables and nothing else. Low is the lowest verified comparable price, high is the highest, and the middle is their median. No adjustment, no model estimate, no rounding toward a figure.
• ✓8. The agent's estimate is shown separately, labelled as theirs. It sits in its own box with the agent's name on it. It never replaces the range, is never averaged into it, and is never presented as what the evidence says.
• ✓9. A quoted price below the evidence is flagged to the agent. If the lowest figure the agent intends to quote sits below the evidence range, the agent is told before anything reaches the vendor, with the sales that sit above it.
• ✓10. Stale data is held, not shown as current. Sales read longer ago than the freshness window are read again or the page is marked stale and held. A one-pager never carries an old read under today's date.
• ✓11. The agent approves the exact version before the vendor sees it. Nothing goes to the vendor without the agent's recorded approval of that version. A change after approval is a new version and needs a new approval.
• ✓12. What was shown, and when, is recorded and never overwritten. On release, the version, every comparable with its source and dates, the range, the agent's estimate, the approval, who it went to and the date are kept. A correction is a new version.
• ✓13. It survives the builder. Someone other than the builder can explain what it does, and it runs on an account the business owns.
• ✓14. The pass test passes. A real one-pager on live sales: every comparable traces to a source record with its sale date, and the record of what was shown is retrieved unchanged later.

Facts that can change, and when we checked them