MobilSense Optimization Tip – Optimal Voice Pool Membership

Not All Voice Devices Belong on Pooled Plans

The most cost-effective strategy for pooling is to use the optimal minute boundaries by pulling off the low and high minute users.  The low minute users can be put on flat rate plans and the high minute users are more cost effective on unlimited plans.  Your voice usage by device, if plotted on a graph like the figure below, would result in a similar looking bell curve.  The majority of devices will produce average monthly usage values that make them strong candidates for membership in a voice pool.  A small portion of devices that we call ‘Pool Busters’, will consume large minutes on a monthly basis.  The cost per minute of these devices is much more economical on the Unlimited Voice plans.  On the other end of the bell curve are devices with little or no voice usage.  These devices are candidates for Flat Rate (pay-per-minute) plans if available to you under your carrier contract.  Below is a conceptual bell curve illustrating our ‘rule of thumb’ break points for determining devices to include in the pool versus devices to place on non-pooled, alternatives plans.



A well-managed pool will typically have a cost/min between $0.06 and $0.12.  The cutover point between pooled and non-pooled devices will vary based on your available plans and your average usage levels.  Because pools have a way of balancing out devices with spikes by those with valleys in a given month, they are your most economical and safe choice for the majority of your voice devices.

The objective with high usage devices is to find a cost/min price point that is lower than your average pool cost/min.  With unlimited plans available for $69.99 or less, an average usage of 1500 minutes will generate a cost/min price point of < $0.05 were pool cost per minute are usually much greater than $0.07, which would be an extremely well-managed pool.  A cutoff point of 1500+ makes sense as long as you have pool tier plans available that let you reduce your overall pool buffer to < 15%.  If you cannot decrease your pool buffer by the commensurate amounts of usage you intend to remove from the pool for unlimited plans then you are going to increase, not reduce your voice costs overall. In these cases they are best left in your pool to chew up excessive buffer amounts.

The logic to define a cutoff point for low-end device usage is to find a voice plan option that is less expensive than the lowest cost plan to be in the pool.  If for example you have an Add-On pool plan for $20 and a Flat Rate plan with a $12 access charge and $0.10/minute rate then at 20 minutes of usage or less your Flat Rate option will be $14 or less, saving $6 or more a month ($12.00 + $2.00 based on 20 min x $0.10/min).  For both high-usage Unlimited devices and low-usage Flat Rate devices you need to monitor them frequently and shift them back into the pool if there usage moves well out of the high or low cutoff ranges or they can become more expensive out of the pool than in the pool.   Effective pool management techniques using a mix of pool and non-pool voice options can contribute 5-10% in voice pool savings.