The KEI or Keyword Efficiency Index (KEI), is an indicator that takes into consideration the Volume of a keyword and your app’s Chance. The KEI is a great indicator of how effective a keyword can be for your app in terms of visibility potential.
The KEI goes from 1 to 100, where 100 is the highest. Keywords with a high KEI are keywords with the best combination of volume and chance. High KEI keywords are likely the most efficient keywords for your app.
You can also check our ASO blog for tips on deeper keyword research and analysis