To accumulate analytics for internal feedback ratings, you'll need to set-up attributes within the SMS flow.
Within the 'Settings' tab > 'SMS Settings' section > Click 'Edit' on the 'Default Customer Flow' > Click Next until you are on Step 3 (shown on the top left) > Choose attributes to include in the SMS flow for customers to select, on Step 3 and 4 > Save Flow.
Now that attribute selections are available to your customers, they will be able to select them when receiving the Edge survey. Data should start to accumulate in the 'Internal Feedback Analytics' section.