There are many differences between blackjack and gumball. but let's stay with our gumball example a little longer to demonstrate two additional concepts: the “pivot” and the "IRC." Though ultra-simple, the 'gumball count system has a fairly serious drawback. While we always know when we have an advantage we often have little in formation about how great (or small) it is. For example, a running count equal to the key count of +1 could occur with 1 white and 0 black balls remaining (an expectation of +100°Io), or with 10 white and 9 black balls left (an expectation of "only" +5.26%).

Indeed, for the game starting with 10 white and 10 black gumballs, the only time we have a precise handle on the expectation is when the running count is exactly 0. At this point, we know our expectation is precisely 0%. We may therefore define the pivot point as the count at which we have reliable information about our expectation. The pivot point is important because, later, we will base betting strategies on this gauge of our expectation.

To further illustrate this effect, let's alter the initial conditions. Instead of 10 white and 10 black, let's assume that there are initially 20 white, 24 black, and 8 yellow gumballs. We can still use our counting system (black = +l, white = -l, yellow = 0) to track the game. But if we start at a count of zero, we no longer have the advantage when the count is just slightly greater than zero. It's easy to see why. If a black ball comes out, our count is +l. However, we are still at a disadvantage in the game since 23 losing black balls remain, compared to only 20 winning white balls (remember, the 8 yellow balls don't matter).