Retrospective report

Week of 7 September 2026

Week-Ahead Model - First Tier

Per-region forecast accuracy for the Week-Ahead Model - First Tier model group over the week of 7 September 2026.

Model revision 4

Generated 14 September 2026 at 7:45 am (Sydney time)

Region	MAE¹	Bias²	Average predicted price	Average actual price	Price spike windows³
NSW1	35.51	10.77	$78.01	$67.24	3
QLD1	17.54	-7.70	$48.83	$56.54	0
SA1	41.99	21.51	$57.53	$36.01	0
TAS1	34.07	27.57	$70.43	$42.86	0
VIC1	21.88	0.20	$43.86	$43.66	0

¹Mean Absolute Error (MAE) is the average absolute difference between forecast and actual prices.

²Bias is the average difference between forecast and actual prices.

³To maintain an informative scale, we charted price spikes separately to other prices. We plotted the 6 hours before and after the RRP exceeded $500 as separate, region-specific charts. These price spikes are capped at $500 in the full region prediction charts.

NSW1

Region	MAE	Bias	Average predicted price	Average actual price	Price spike windows
NSW1	35.51	10.77	$78.01	$67.24	3

Change in Forecasted Prices over the Price Spike in NSW1 between 2026-09-08 01:00:00 and 2026-09-08 13:00:00

Change in Forecasted Prices over the Price Spike in NSW1 between 2026-09-11 01:00:00 and 2026-09-11 13:00:00

Change in Forecasted Prices over the Prediction Interval in NSW1 using Week-Ahead Model - First Tier (Without Price Spikes)

QLD1

Region	MAE	Bias	Average predicted price	Average actual price	Price spike windows
QLD1	17.54	-7.70	$48.83	$56.54	0

SA1

Region	MAE	Bias	Average predicted price	Average actual price	Price spike windows
SA1	41.99	21.51	$57.53	$36.01	0

Change in Forecasted Prices over the Prediction Interval in SA1 using Week-Ahead Model - First Tier

TAS1

Region	MAE	Bias	Average predicted price	Average actual price	Price spike windows
TAS1	34.07	27.57	$70.43	$42.86	0

VIC1

Region	MAE	Bias	Average predicted price	Average actual price	Price spike windows
VIC1	21.88	0.20	$43.86	$43.66	0