Referenced by 4 other explainers
LGA anchoring is how Place Forecast keeps small-area estimates in line with published ABS totals for the LGA.
Place Forecast starts with small-area estimates. It then checks each category against the ABS total for the whole LGA. The small-area estimates may not add up to the ABS LGA figure. When they do not, Place Forecast scales them so the category total matches the ABS figure.
Small gaps can still show up between totals and category sums. This is because the ABS changes small Census counts to protect privacy. This is called perturbation. Place Forecast anchors on the category figures so each category matches the ABS total. It lets the page total carry the gap.
LGA anchoring does not make each small-area value an exact ABS count. Small-area figures are still estimates. Use them to see patterns across the LGA. Do not read them as direct ABS counts.