In some ways, you could say that today’s Grammar 101 post is related to maintaining parallel structure, but that had to do with matching up the structure of the list items for consistency. Today, it’s more about making sure that you are conveying the right meaning.
The best way to illustrate the problem with list items is with an example that I found in a news article some time back.
Social factors such as social support, absence of corruption and personal freedoms are more important.
Do you see the problem? Strictly speaking, this sentence is grammatically correct, but it can lead some confusion and ambiguity. By using “absence of” in the second item, some readers may extend that to the third item. As such, a reader may understand the sentence to mean this:
Social factors such as social support, absence of corruption and absence of personal freedoms are more important.
Logically speaking, the “absence of personal freedoms” doesn’t make too much sense in this context. As I said, the sentence as it stands is technically correct, but the ambiguity can be easily alleviated by simply rearranging the items:
Social factors such as social support, personal freedoms, and absence of corruption are more important.
I added the Oxford comma there to further improve the understanding of the sentence, but it’s not really necessary.
Perfect grammar, good writing, and clear understanding do not always go hand-in-hand-in-hand. It’s wonderful when you are able to have all three, but realize that even if your sentence is grammatically correct, it may not be the best sentence for its intended purpose.