I built the tool I wished existed.

The gap between policy and practice

I’ve sat on every side of the planning table. Designing schemes as an ARB-registered architect. Assessing them at a London council. Acquiring sites and managing planning as a developer. I authored the London Borough of Merton’s Small Sites Supplementary Planning Document, the policy framework councils now use to assess the schemes Perfect Scale codes.

At every stage, I saw the same problem: published policy tells you what a borough wants, but it doesn’t tell you what it actually approves. The gap between the two is where schemes fail, money is wasted, and homes don’t get built.

Everyone touching a small site, the developer weighing a bid, the owner deciding whether to sell, the agent advising either, the officer assessing the application, is working off policy documents, market chatter and instinct. The decided record exists. Nobody was reading it back to them.

Whose side we are on

Because I have stood on every side of that table, Perfect Scale is built to take none. The evidence does not change with who is asking. The same site returns the same number to a developer weighing a bid, a seller pricing a disposal, an agent advising either, or a planning authority benchmarking its own decisions. We do not argue a client’s case, we do not tell you what you hoped to hear, and we publish the limits of the data as plainly as the findings. An independent measure is only worth something if it reads the same to the party it helps and the party it does not. That is the sacrifice the position demands, and we pay it on purpose.

What Perfect Scale does

We analyse every determined small-site application in a borough over 3 to 5 years. Each one is coded by type, area, density, and outcome. Every officer report is read. Every finding is evidence-graded.

The result is a set of public borough dashboards plus site-specific assessments, telling you, for any given site type and location, what density has actually been approved, what the refusal risks are, and where the viability cliffs sit.

No hand-waving. No unqualified claims. Four evidence tiers, from Robust to Anecdotal, so you know exactly how much weight to put on each finding.

Why evidence grading matters

The property industry is full of claims without evidence. “This area approves density.” “Pre-app is a waste of time.” “Conservation areas always get refused.”

Some of these turn out to be true. Some are completely wrong. The only way to tell is to look at the data. Every Perfect Scale finding comes with a sample size, a statistical test where appropriate, and an evidence tier. If the data is thin, we say so.

This matters because the decisions resting on it are worth hundreds of thousands of pounds, on whichever side of the table they are made. Anyone relying on the evidence needs to know the difference between a finding backed by 200 applications and one based on a handful.

Methodology

Each dashboard and assessment is built from a complete dataset of determined applications, sourced from the GLA Planning Datahub and each council’s own planning register. We use a combination of automated data processing and AI-assisted document analysis, with manual verification at every stage. Full methodology (sources, NLP pipeline, taxonomy, models, back-test, and limits) is documented on the Methodology page.

Our density benchmark is back-tested against every approved application before publication. Across the borough dashboards it lands within ±1 unit of the actual approved scheme 73% of the time, and within ±2 units 90% of the time, with no systematic bias.

We grade accuracy by evidence tier. Robust cells are 37% more accurate than Anecdotal, so you know where to trust the numbers most.