Apparently some people believe that “complex” and “complicated” have different meanings. Many years ago a friend of mine mentioned in passing that there was a difference. However, dictionaries do not make such a distinction. Apparently my friend and some academics do.
I am not sure just when this started, but I found somewhere a reference from the 1940s. However, searching for the difference, it seems that there is little agreement, some giving “complicated” the burden of meaning that others reserve for “complex,” and vice versa. What a mess!
There is a discipline called “complexity theory,” which seems to be coming from the mathematicians and the computer scientists, although it has been creeping into business literature and economics.
A distinction between the two words was discussed in a report in July of 2002 on the healthcare system in Canada. See https://www.alnap.org/system/files/content/resource/files/main/complicatedandcomplexsystems-zimmermanreport-medicare-reform.pdf
The idea of complexity could of course be quite bastardized once taken away from the domain of mathematics.
Who told the academics that they could once again usurp the the meaning of common words. Of course, they do this all of the time, don’t they? 😉