Calls that are highlighted yellow and display multiple attributions like the image below occur when your ratio of visitors to available numbers into your tracking pool is too high.  In this scenario, Call Dynamics will allocate some tracking numbers to multiple visitors and the algorithm can often tell the callers and visitors apart, but in some cases where the ratio far exceeds the algorithms capacity, the visitors it considers probable will be reported instead of nothing at all.

This is indicated by calls that have an attribution that looks like this;

In this case, there were multiple visitors and the algorithm was unable to tell two of them apart, so both have been reported.

In many cases, this can occur from time to time without causing any major data or reporting problems for the client, however, if it starts to occur frequently, the pool utilisation should be monitored and additional tracking numbers added to the pool as required.

To monitor the pool utilisation, set a reasonable timespan (for example, last 30 days) in your Call Dynamics control panel, and then on the Reports tool item, click in to Call Log, and then filter by Campaign, and then down to the specific Pool you'd like to check the utilisation on.  

From the image above, we can see that we've filtered the reports down to the Campaign called "Website Tracking" and the Pool called "Main Website", and that's caused a tab called "Pool Utilisation" to appear at the top-right hand side of the dashboard reports.   Click on the "Pool Utilisation" tab and you'll see an averaged pool utilisation across the timespan that you selected.   This pool is frequently hitting 100% utilisation, and as such, it is advisable to add additional tracking numbers to the pool.

To add additional tracking numbers, click the 'Orders' tool icon from the lower left of your portal, and then search and select the number you'd like to add.   Once you've added the additional number(s) to your account, you then need to edit the appropriate pool configuration and add the number(s) to that pool, then save the pool.

It is wise to add a diary note to come and check your pool utilisation again in the following days or weeks to ensure your utilisation remains less than 100% on average.   If you find that your website traffic is steadily increasing over time AND that your pool utilisation is sitting around the 75%-80% mark, we would recommend adding 2-3 additional numbers early on to ensure you don't meet the same problem again in the coming months.