06/08/2026
The Model That Cannot See Money
Project Stamina's venue recommendations rest on a P-median
optimisation model. The report describes it at pgs 52 and 108 - 110,
and sets out its parameters in Table 9 on pg. 66.
P-median is one of the oldest & best understood tools in operations
research, first created in the 1960s.
It was built for, and good at, problems like where to locate ambulance
stations, fast food resturants (supermarkets & petrol stations may use
it too). Cases where the service delivered is identical to wherever
you put it (think McDonalds), where the users have no real choice but
to attend the nearest one, and where the thing you are trying to
minimise really… is travel.
It cannot tell you how many facilities you should have; The p in
P-median is an input, not an output. You must decide the number in
advance. The model places that number optimally. Ask for 4 and you get
4 Ask for 6 and you get 6. The model has no view on which is correct,
and it will confidently produce an optimal 4-facility network for a
system that needs 6.
It cannot distinguish between facilities; In the classic formulation
every facility is identical, the standard model has no variable for
what a facility produces, what it costs, how good it is, or what it
earns.
It cannot value anything; There is no revenue term.. The objective is
distance. A P-median model cant tell you that a facility is worth
keeping, because worth is not a concept it contains.
A P-median model optimises for physical proximity. It assumes that
being close to the facility is what generates the value.
Distance to a racecourse is close to irrelevant to a punter in
Melbourne, who is opening an app at 9pm to have a punt. What matters
to that punter is whether the racing is worth betting on.
Project Stamina states that wagering has decoupled from on-course
attendance & that the majority of domestic wagering is now off-course.
It says it in the narrative & then builds the decision on a location
proximity model anyway.
The second structural problem is how the model's output was used.
P-median assigns demand to facilities as a consequence of where it put
the hubs. Race day allocation is not a measurement of anything.
Project Stamina focused the Central Districts on Awapuni as both a
metropolitan venue and a training centre. Race days were then added to
that anchor by construction. Trentham was left with four.
Pg. 73:: "Trentham, insufficient demand to sustain minimum 8 race day
threshold, only allocated 4 race days."
The model produced the four. The four was then treated as evidence of
insufficient demand.
That is the result of the model reading back its own input. No
performance measures that Trentham could achieve would change the
allocation, the allocation was determined by the anchor decision
before any performance was considered.
Every one of the eight venues recommended for exit failed the eight
day threshold.That is not eight venues failing a test. That is one
modelling decision producing eight consequences.
Page 97- The model is "a decision-support tool, not a predictive instrument."
It "has not been independently audited." "All quantitative outputs are
sensitive to the assumptions on which they are based, and small
changes to key assumptions may produce materially different results."
The report told everyone that small changes to the assumptions may
produce different results, and then never varied the key assumptions.
A P-median model is the right tool: if you were building a racing
network from scratch.
The better approach would be to use the model to generate a direction,
then overlay everything the model cannot see
e.g what each venue produces,
what it costs to run,
what condition it is in,
what programme it carries,
what happens to the network when a track fails, and
what the wagering consequence of each change would be.
For 5 of the 8 venues recommended for exit, NZTR did apply judgement
and then overrode the model, retaining Whanganui, Ashburton, Te Aroha,
Ōtaki and Timaru on network capacity, jumping role and regional
balance.The other 3 incl. Trentham, have no reason/criteria of
assessment has been published…yet.
What is needed:
#1 Publish the projected Central Districts wagering turnover with
Trentham retained vs. Trentham exited, and reconcile it against three
seasons of NZTR's club statistics.
#2. Publish the criteria that separated the five venues retained
against the model's advice from the three that were not.
#3 Commission the independent audit of the optimisation model that the
report notes has not been done.
[Everything I post is compiled from publicly available sources. Other
than being a small thoroughbred race owner and breeder with one
broodmare, I have no commercial, governance or financial interest in
these matters, and I do not represent any club, organisation or
stakeholder group.]