punctuation - Sentence with multiple 'and's: should I use an Oxford comma, and if so, where?

I have the following sentence:

I am a self-starter possessing excellent problem solving ability and outstanding coordination and communication skills.

Using the Oxford comma, what is the correct way to write it?

I am a self-starter possessing excellent problem solving ability, and outstanding coordination and communication skills.

I am a self-starter possessing excellent problem solving ability and outstanding coordination, and communication skills.

Answer

The serial comma only comes into play if you have an actual list, i.e. three or more items. You only have two:

excellent problem solving ability

and

outstanding coordination and communications skills

To see this, look at the nouns, not the phrases describing them: ability and skills are two things.

Within the phrase "outstanding coordination and communications skills", it is absolutely wrong to insert a comma before the "and". For the sentence as a whole, though, the issue isn't quite so clear-cut: it's not really a list, so adding a comma is unnecessary, but on the other hand, it can aid comprehension to group the adjectival phrases — basically, to make it clear that excellent problem solving goes with ability, while outstanding coordination and communications all go with skills.