Visitor level call tracking requires a pool of tracking numbers that can be used to allocate to each visitor that comes to the website. Tracking pools are dedicated to each website and client so that all calls are guaranteed to connect through to the clients call centre or office.
Phone numbers are recycled back into the pool after they expire to reduce the number of phone numbers required to track accurately. Using this approach, we can track millions of keywords using only hundreds or thousands of phone numbers rather than needing millions of phone numbers.
The number of phone numbers that are needed in a dynamic number pool depends on how busy the site is and on average how long a visitor stays on the site browsing.
Using an existing analytics systems such as GA, we can establish the peak number of concurrent visitors on the website in an hour and the average browsing time. This allows us to work out how many tracking numbers need to be added to the pool initially if it is a slightly busier website than usual, however the majority of the time we add between 20-50 numbers and let our algorithm do the rest. Our algorithm runs and look at the peak number of concurrent visitors to the website within a period of time and alerts us if more numbers are required.
Infinity has approached this from the beginning, with a balance of accuracy against cost; we think the sweet spot is for the dynamic number to stay with the visitor for the length of the browsing session and average of 10-15 minutes after. In tests this gave a 97-99% accuracy of matching the call to the correct visitor.