I don't have data or specific experience in this area except a memory of writing and reviewing survey questions to assess the efficacy of ISTE technology standards of Grade 3-12 teachers. Defined rubrics were very helpful to define a quantifiable scale and maintain validity and reliability.

What seems to distinquish complex from complicated is the severity of impact that is realized when the worker begins to isolate the variables to effect a change in performance in themselves or others.

The research that supports The Performance Consultant's Fieldbook By Judith A. Hale include some study references that may include related data.

It is much easier with software than with people for the main reason that people are unpredictable. I like the following blog: Here is one of the entries of complex vs complicated that I thought was pretty insightful.
https://www.noop.nl/2008/08/simple-vs-complicated-vs-complex-vs-chaotic.html

Dividing work that is not concrete, like software is messier.

Good luck!