Q: Do I need a comma after the word “expert” in this sentence: “I spoke with an expert and if I were a betting man, I would pick the Cowboys.” The few “experts” I have consulted seem unsure of the rule for punctuating a complex sentence like that.
A: Sometimes commas are optional, and your sentence is a good example. There’s no specific “rule” for punctuating a sentence like that.
If it were up to us, here’s what we would suggest: “I spoke with an expert, and if I were a betting man I would pick the Cowboys.”
Why? Because of the three clauses, the last two are more closely connected than the first two. We would separate the first clause from the rest, because we sense a natural division there.
However, other writers might disagree; they might prefer a differently placed comma, or two commas, or none at all.
Even when only two clauses of this type are involved, the use of commas is a matter of preference rather than correctness.
You might choose this, for example: “If I were a betting man I would pick the Cowboys.” But this would be equally correct: “If I were a betting man, I would pick the Cowboys.”
There’s a certain amount of flexibility in the use of commas to separate clauses. As The Cambridge Grammar of the English Language says, “punctuation practice is by no means entirely uniform.”
For example, the Cambridge Grammar notes the “distinction between light and heavy punctuation styles.” It gives these examples:
light or “open” style: “On Sundays they like to have a picnic lunch in the park if it’s fine.”
heavy or “closed” style: “On Sundays, they like to have a picnic lunch in the park, if it’s fine.”
“This distinction,” the authors explain, “has to do with optional punctuation, especially commas: a light style puts in relatively few commas (or other marks) in those places where they are optional rather than obligatory.”
When in doubt, let your ear decide. If you feel a pause is in order, exercise your option and stick in a comma.