Correlating parameters based on participant rather then observation

Hello everyone,
This question may be rudimentary, however I haven't touched statistics for a very long time and therefore became quite incompetent.
In my experiment participants were asked to rate several parameters multiple times (each time after completing a task).
I'm looking to correlate this parameters however as i mentioned most of my observations are task based (lets say, difficulty to complete each task) but some are participant based (number of total task completed correctly, rating of the experience as a whole). I'm essentially looking for a way to create a "total score" for each participant in the for the task based parameters. Whats is the "right" statistical approach for it? is creating an average good enough?

Thanks in advance,