Model Predictions

9th round predictions for Super Netball.

To refresh your memory, here’s a description of how my model works.

Standard Model

Predictions for the 9th round are given in the table below. The priors for these distributions are based on the final abilities from last season and the results from rounds 1–8. However, given the Super Shot, it’ll take a little while for the model to adapt to the adjusted goals.

Home	Away	Chance of home team winning
GIANTS Netball	Melbourne Vixens	34%
Collingwood Magpies	NSW Swifts	32%
Adelaide Thunderbirds	Sunshine Coast Lightning	28%
Queensland Firebirds	West Coast Fever	18%

Score Differential Distributions

The distribution of the predicted score differentials is shown in the figures below. For each game, the chance of the home team winning is calculated and shown in the figure title. Each distribution is coloured by the team’s colours, and the more of a single team’s colour, the higher the chance that team has of winning. Overlaid on each figure are two vertical, dashed dark green lines; these show the score differential that has a 50% predicted chance of happening.

Non-HGA Model

I’ve also built a model that doesn’t utilise a home ground advantage parameter. Given the majority of teams don’t have a home crowd cheering them on, it seems unlikely that there’s any advantage to being named the ‘home team’ in a game. The non-hga predictions are below.

Model Comparisons

In this section we look at how the model estimates team ability from the previous round, as well as model performance.

Team Ability

Team ability can be understood as the expected score difference that the team contributes to the final expected match score difference. For example, if the Vixens are playing at home and have an estimated ability of 1 against the Magpies who have an estimated ability of -1, the expected match difference will be 2 (1 - -1).

Latest Team Ability

The figure below shows the latest team ability estimate. The points are the median predicted ability (as estimated by the model). The dark shading shows 50% prediction intervals, the lighter shading shows 50% prediction intervals.

Season Team Abilities

The figure below shows how team ability has evolved over the season to date.

Comparison of Game Results Against Predictions

The following figure shows the results (score difference of the home team) in round 8 (blue vertical line) against the predictions from the model.

The mean average prediction error for the model over the rounds to date is 12.15. The results are shown below, with the MAPE for each game.

Home	Away	Chance of home team winning	Home Goals	Away Goals	MAPE
Melbourne Vixens	NSW Swifts	66%	63	60	7.6
Collingwood Magpies	GIANTS Netball	28%	54	69	11.3
Queensland Firebirds	Adelaide Thunderbirds	36%	54	53	8.5
West Coast Fever	Sunshine Coast Lightning	18%	80	56	32.7