How development sites are included in your forecast and how to give feedback

Housing development drives local population change, so the development assumptions are the part of your forecast where council knowledge matters most. This article explains how individual sites and smaller-scale growth are included, what the mapped sites do and do not mean, and what feedback is most useful when your area's review comes around.

Key concepts

The Residential Development Layer

We track significant residential development across Australia in our Residential Development Layer, with each site's capacity, status and likely timing. A site enters the layer when it has a potential yield of 10 or more additional dwellings, and its timing reflects the site’s status at the time of forecast preparation: under construction; going through or has recently received formal development approval; it sits within a strategic land supply precinct identified in planning instruments or growth strategies; or it is assessed as underutilised under current planning controls.

The infill layer

Growth also happens below the 10-dwelling threshold, through dual occupancies, small unit developments and similar projects. We estimate this through an infill methodology that considers zoning, lot configurations, existing approvals and historic rates of infill development, and we apply it as a rate of growth distributed across small areas rather than site by site.

Capacity is not uptake

The Residential Development Layer identifies potential future capacity, and it deliberately includes some speculative and very long-term sites. A site appearing in the layer does not mean its full capacity is assumed in the forecast: the forecaster judges how much of each site's capacity is taken up within the forecast period and when, based on its status, development trends and the constraints on total regional growth.

How the assumptions are maintained

We maintain the development assumptions from satellite imagery, development application portals and state and local government planning documents, updating continually as zoning changes and sites progress. Council knowledge is the other half of the picture: feedback on sites, yields and timing is collected ahead of each area's review window and feeds into the next forecast release.

What feedback is most useful

There is no need to work through every site in detail. The most valuable feedback is anything missed or incorrect: a site we do not have, a capacity that is wrong or timing that no longer reflects what is happening on the ground. Future estate areas still in the planning process, precinct plans and any sequencing documentation are particularly useful, because public information on these is thinnest. Sites that are already subdivided are easier for us to track, so they need less attention in your feedback. Corrections to assumed capacities, gaps in mapping and the likely timing of development are the three things to check. Council datasets can also help: constraint information your council holds, such as hazard mapping, can inform how capacity is assessed. Many Local Government Areas allow only very limited public view of development applications received and resolved - if this is the case for yours, our assumptions would benefit significantly from a list of what’s been approved in your area.

Where this appears in Population Forecast

Details of the underlying assumptions and methodology are included with your Population Forecast site, which is where the site and infill assumptions become visible in your figures. When your area's review approaches, we contact your council for development site feedback, with the opportunity to check locations, yields and staging before the next release is prepared.

Frequently Asked Questions

Q: A site near us is in the development layer but the forecast growth seems low. Why?

A: The layer records potential capacity, including some speculative and long-term sites. In most cases, housing capacity identified through our development sites review exceeds the expected uptake within the forecast period. The forecast reflects a judgement about how much of that capacity is realistically delivered within the forecast period, so a large mapped site can contribute only part of its capacity, or none yet, to the published figures.

Q: A development under 10 dwellings is missing from the sites. Is it excluded from the forecast?

A: It is not excluded, it is just handled differently. Developments under 10 dwellings are covered by the infill layer, which applies an assumed rate of small-scale growth across each area rather than mapping every small project individually.

Q: When can we give feedback on the sites?

A: Ahead of your area's review window: we contact councils for development site feedback as each review approaches. Note that forecast delivery does not directly follow feedback submission, as each review runs on its own schedule. If something significant is missing or wrong in the meantime, tell your .id contact.

Q: What should our feedback include?

A: Focus on what we are least able to see: missed sites, incorrect capacities, timing that has changed and planning or sequencing documents for future estate areas and precincts. Location, expected dwelling yield and development stage are the three details that matter for each site. Draft policies are also helpful where there is expected change to existing documents.