Why Is My Population Projection So High or Low?
You open your Place Forecast, navigate to a small area, and the population projection stops you in your tracks. That number can’t be right, can it? Perhaps the forecast shows thousands of new residents by the end of the forecast period, but your local planning strategy only anticipates modest growth. Or maybe you know about major developments planned for the area, yet the forecast barely shows any increase. Either way, it doesn’t match what you know about the place. That’s a fair reaction, and there is a good explanation. Here is what is going on.
Place Forecast Is Housing-Led
Population projections are shaped by dwelling projections. The baseline forecast projects future dwellings by repeating recent building approval activity. It takes the last twelve months of building approvals and holds that level steady into the future, then converts those approvals into building completions using observed construction timelines.
This means the baseline forecast does not know about your local knowledge: planned developments that haven’t started yet, capacity constraints that will slow growth, or rezoning decisions that will change the character of an area. The baseline simply continues what it can observe from the data.
Why Does the Projection Seem Too High?
If your small area experienced a spike in building approvals in recent years, perhaps from a large apartment development or a redevelopment precinct, the baseline repeats that elevated level of building approval activity into the future. In reality, the development may be nearing completion, approvals may return to normal levels, or the area may be approaching its physical capacity. Without being told otherwise, the forecast holds that level steady.
The solution: use housing and dwelling assumptions to apply a ceiling that caps dwellings at a maximum, or a reduction that lowers the projected dwelling count from a certain year onwards.
Why Does the Projection Seem Too Low?
If your small area has been relatively quiet in recent years, with few building approvals and little construction activity, the baseline repeats that low level of activity into the future. But you may know about planned developments, approved building sites, or rezoning changes that will bring significant new dwellings to the area in coming years. The forecast simply has not been told about these yet.
The solution: use housing and dwelling assumptions to add future dwellings based on your local knowledge of planned developments, approved sites, and expected construction timelines. If you know the exact dwelling target for an area, you can also use an override to set the projected dwelling count to a specific number.
The Solution: Housing and Dwelling Assumptions
Housing and dwelling assumptions are an input to your forecast that lets you adjust the dwelling projections for any small area. You can tell the forecast about future building sites, capacity constraints, or expected changes in development activity. There are four types of adjustments available:
- Addition: add dwellings on top of the current baseline projections (e.g., a planned development site)
- Reduction: reduce dwellings from the current baseline projections (e.g., a construction delay or demolition)
- Override: replace the projected dwelling count with a specific target number
- Ceiling: cap the projected dwellings at a maximum (e.g., the area’s physical capacity)
These adjustments flow directly through to the population projections, via average household size. All else equal, more dwellings means more people; fewer dwellings means fewer people.
For full details on how to prepare and upload your assumptions, see Council Housing and Dwelling Assumptions.
What to Do Next
Review the dwelling projections for your small areas. If they don’t match your local knowledge of planned or expected development, prepare a housing and dwelling assumptions dataset. We can help you get started and walk you through the process. Get in touch.