Why PropertyResearch Now Uses Rolling Market Data Instead of Calendar Years

Why I Moved From Calendar Years to Rolling Market Data

Property markets do not move neatly within calendar years. Prices rise and fall continuously, transaction volumes shift month by month, and market momentum can change quickly.

Until now, several areas of the site analysed data using fixed calendar years. While this approach is simple to understand, it can sometimes hide what is actually happening in the market today.

For example, if the current year is only partially complete, a calendar-year analysis may compare a full year of historical sales with only a few months of the current year, creating misleading signals.

To improve accuracy and ensure the platform reflects current market conditions, PropertyResearch has now moved to a rolling data model across several major areas of the site.

Where the Change Has Been Applied

Rolling data has now been implemented across the following sections:

• Property Dashboard
• Prime Central London (PCL)
• Ultra Prime Central London (UPCL)
• Outer Prime London

These pages now analyse the market using a rolling 12-month period, rather than fixed January-to-December data.

This means the figures always reflect the most recent twelve months of activity, regardless of where we are in the calendar year.

I will likely change other pages to this method where appropriate.

Why Rolling Data Is More Accurate

Using rolling periods removes the distortions that occur when analysing incomplete calendar years.

The advantages include:

1. Always Up-to-Date Market Data

Rolling analysis automatically incorporates the most recent Land Registry transactions as they become available.

This ensures that users are seeing the latest state of the market, not a snapshot from several months ago.

2. Eliminates Partial-Year Distortion

In a traditional calendar-year model, the current year often looks artificially weak simply because it is incomplete.

Rolling data ensures every comparison uses a full twelve months of activity, making trends far more reliable.

3. Better Trend Detection

Because the time window constantly moves forward, the system is able to detect:

• emerging price movements
• demand slowdowns
• liquidity shifts
• accelerating market momentum

much earlier than a calendar-year approach.

A New Market Summary Panel

Alongside the change to rolling data, a new headline summary panel has been added to the top of each page.

This panel provides an instant overview of the current market conditions for the area being analysed.

It displays four key indicators derived from the most recent 12-month data:

• Last 12 Months Sales – the total number of transactions recorded in the area
• Median Price – the midpoint sale price across all transactions
• Median Price Change – the percentage change compared with the previous period
• Sales Volume Change – the change in transaction volume compared with the previous period

Together, these metrics provide a quick snapshot of both price direction and market activity.

For example, it is possible for prices to remain stable while transaction volumes fall sharply, indicating a cooling market with reduced liquidity.

A Clearer Picture of the Property Market

The goal of PropertyResearch has always been to move beyond simple averages and provide deeper insights into how property markets behave.

Switching to rolling data ensures that the analysis reflects real market conditions as they evolve, rather than being tied to arbitrary calendar boundaries.

Combined with the new summary panel, users can now immediately understand:

• how active the market currently is
• whether prices are rising or stabilising
• whether demand is strengthening or weakening

all from the moment they open a page.

As the dataset continues to grow and more analytics are introduced, this rolling-data approach will provide a stronger foundation for identifying meaningful market trends across the UK property market.