An athlete that I train asked Ironman about the procedure of the allocation because he thought his age-group should have been given 2 slots. Ironman answered how they are doing the math:
As you may have noted in the Athlete Guide, once the “Initially Allocated Slots” are allocated (1 per age group having at least 1 starter), the “Proportionally Allocated Slots” are then provisionally allocated across all men’s age groups (“AG”) based on the number of starters for each age group. This is done by allocating each Proportionally Allocated Slot, one by one, to the men’s AG with the then-highest ratio of starters to slots (“Ratio”).
To illustrate: You’ll see above M40-44 began with the highest Ratio (109 to 1). So the first Proportionally Allocated Slot went to M40-44. After M40-44 received its first Proportionally Allocated Slot, that AG (M40-44) then had a Ratio of 54.5 to 1. Which means the next Proportionally Allocated Slot went to the AG with the then-highest Ratio, which was M45-49 (96 to 1). And so on.
After distribution of all Proportionally Allocated Slots, M30-34 had the then-highest ratio (38 to 1). But at that point there were no more Proportionally Allocated Slots remaining to allocate for the men.
The next procedure applied is stated on page 49 of the Athlete Guide, which states in pertinent part:
“If any slot allocated to an Age Group is unclaimed (after Roll Down for that Age Group is completed), then that unclaimed slot is re-allocated, within the same gender, to the Age Group with the highest ratio of starters to slots.”
Accordingly, had any slot in the table above not been accepted by any finisher in a given AG, that unclaimed slot then would’ve been re-allocated to M30-34, because, as stated above, M30-34 had the then-highest ratio of starters-to-slots (38 to 1). For example, if both finishers in M70-74 had rejected that AG’s sole slot (i.e., if it had “rolled down” through the entire AG), that slot would’ve been re-allocated to M30-34.
As it happened, all men’s slots offered at IRONMAN Malaysia were accepted at roll-down within the respective age groups.
Accordingly, there was no re-allocation of slots between different age groups.
As an aside: At first glance it might seem incorrect that, for example, M50-54 had 77 starters and 3 slots, whereas M30-34 had 38 starters but only 1 slot. That third slot for M50-54 was the last Proportionally Allocated Slot to be allocated. Before that third slot was allocated to M50-54, that AG’s Ratio was 77 to 2, or 38.5 to 1. Which meant that, at that point, M50-54 had the then-highest Ratio, barely edging out the 38 to 1 Ratio in M30-34.