The Victor Insurance Parameter
by Rich Victor
(From Blackjack Forum Vol. XXII #1, Spring 2002, Updated Fall 2007)
©Copyright 2007 Blackjack Forum
If you are a blackjack player who side-counts aces and uses a balanced, ace-neutral primary count, the Victor Insurance Parameter (VIP) can improve your game. The Victor Insurance Parameter is defined as the running count divided by the number of unseen aces. It provides a much simpler and more accurate assessment of the insurance situation than the customary match-up of true count and insurance index.
Like many blackjack card-counting techniques, traditional insurance decision-making is both cumbersome and imprecise. It involves estimates of undealt cards, true-count computations, and multiple indices for different numbers of decks — while still failing to account for the impact of ace-density. Yet as the Victor Insurance Parameter demonstrates, this unwieldy process can be avoided entirely. For ace side-counters, implausible as it may seem, the size of the remaining pack (or shoe), the true count, and the original number of decks in play are all immaterial to an optimal insurance decision.
An insurance bet is indicated whenever the VIP exceeds the applicable “threshold-value,” which varies from one counting system to another. But the appropriate threshold-value for a given system is the same regardless of the number of decks in play. In the infrequent event that there are no unseen aces, insurance should be taken on any positive count.
In his excellent article, A Theoretical Basis for the Victor Insurance Parameter, ET Fan not only presents an elegant mathematical proof of the validity of the VIP concept, but also identifies a simple method for determining the optimal threshold-value for any balanced, ace-neutral counting system. Additionally, he provides exact threshold-values for several of those systems:
Hi-Opt I: 2/3 (rounded to 0.67);
Canfield: 5/6 (0.83);
Hi-Opt II: 7/6 (1.17);
Omega II: 4/3 (1.33);
Uston APC: 16/9 (1.78);
Victor APC: 11/6 (1.83).
Although insurance should be taken whenever the VIP exceeds the applicable threshold-value, an alternative, equivalent (and possibly easier) guideline is available for several of the above systems:
- For Hi-Opt I: Insure when 1.5 times the running count exceeds the number of unseen aces.
- For the Canfield count: Insure when 1.2 times the running count exceeds the number of unseen aces.
- For Omega II: Insure when 75% of the running count exceeds the number of unseen aces.
- For the Victor APC: Insure when 55% of the running count exceeds the number of unseen aces.
To summarize, these are the ways in which the Victor Insurance Parameter can benefit a capable ace side-counter:
1. It eliminates the need to estimate (or mis-estimate) the size of the remaining pack and compute the true count. The ace side-counter already knows the number of unseen aces.
2. It’s independent of the original number of decks in play. There’s no need for multiple indices; one size fits all.
3. It fully accounts for the impact of aces as non-tens, a factor that cannot be addressed without an ace side-count.
4. It not only eliminates errors of estimation, but also adds roughly two percentage points to the insurance correlation of any balanced, ace-neutral counting system. For example, the insurance correlation of Omega II rises from 85% to 87%, while the Victor APC’s insurance correlation goes from 89% to 91% with the VIP.
On average, the dealer will show an ace once every 13 hands — so it’s no small matter to be able to evaluate those situations quickly and accurately. The Victor Insurance Parameter is your shortest path to insurance efficiency. ♠
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