JQL for Using a Checkbox to Track Time

[Jenna Frenak]

Hello!

So in certain projects in JIRA, a checkbox called "Out for Review" is used within issues to indicate that documentation has been attached to the story for the developers to review its accuracy. There is also one called "Review Completed" that is selected when the developer is done reviewing the documentation. These fields can be used at any point during the workflow.

 We want to be able to track how long passed between the first and second checkbox were both selected, i.e. how long it took the developer to review the document.

Under the History tab/section on a story we're able to see the date and time that each of the boxes were selected so I'm assuming there's SOME way to do this with a JQL query and not just a manual calculation. 

Any help is appreciated and please let me know if anyone needs any clarification on anything!! 

Thank you so much!