Is there any data on which paradigms allow for code which is easier/cheaper to maintain? Certainly, independantly of the chosen paradigm, good design is cheaper to maintain than bad, but there should probably be major differences coming only from the paradigm choice.

Unstructured programming, for instance, generates very messy code (spaghetti code) which is expensive to maintain.

In object oriented programming, implementation details are hidden and thus it should be pretty cheap to change those.

In functional programming, there are no side effects, thus there is lesser risk of introducing bugs during maintainance, which should be cheaper.

Is there any data on which paradigms are the most cost-efficient when coming down to maintenance? If no such data exists, what is your take on the question?