What LMS results can you look for that show eLearning engagement levels?

After an eLearning course has been deployed and has been gathering results in your LMS for a while, what types of things can you look for to see if learners are engaged in the eLearning you created?

Are there indicators that exist that would show if the learner was "engaged" in the interactive elements/exercises that were built for them? 

For example, showing an increase in engagement for eLearning than has an interactive calculator to practice on; as opposed to eLearning that just has screens with text/voiceover describing to the learner reads about using the calculator.

While I feel that it's obvious that learners are more engaged by interactivity, it would be nice to see the results of this, or be able to gauge it in some way via LMS.

In the LMS, we're able to see duration that the learners have spent in each module. Specific eLearning modules that I'd like to see results for also track "complete/incomplete" after learners finish (it was a request to not have the knowledge checks graded/show percentage).

Does the amount of time that a learner spends in an eLearning module necessarily show how "engaged" they were?  For example, if they spent a noticeable extra amount of time in a module than the recorded average run-through time it took to complete it?