Custom metrics allow you to customize and specify the data shown in your widgets in Skyview and Insights even further. You are now able to choose a metric -, +  or / another metric.
Maybe you want to show all inbound Offered calls - Unmanaged calls. This will show all inbound calls that have been answered, abandoned or gone to timeout, but it will exclude the unmanaged calls (e.g. callbacks).
Or maybe you want to show all answered calls, including Callbacks - then you would choose the custom metric Answered calls + Unmanaged calls.

How to create Custom Metrics

Go to Skyview or Insights (the function works the same in both tools) and click on the three dots next to the widget you want to edit. Click Edit Widget

Or create a new widget by clicking Add widget on the bottom of the page.

Click on the + next to the Custom metrics field

1. Choose the name of the custom metric
2. Choose Custom or Complex
Custom includes the standard metrics and Complex includes both standard metrics and your previously created custom metrics (which means you can create two levels of custom metrics)
3. Choose operation by clicking on the +, - or /

4. Choose the metrics
5. Then click Save

The Custom metric will then be saved along with your other custom metrics

Choose your custom metric and click Save

And that's it! 

Hope this was helpful!