Here's why:
* Parallel structure means using the same grammatical structure for items in a list or series. It makes your writing clear, concise, and easy to understand.
* Splitting infinitives means putting a word or phrase between the word "to" and the verb in an infinitive (e.g., "to boldly go"). While this practice was once considered a grammatical error, it's now widely accepted in many cases.
However, splitting infinitives can disrupt parallel structure if it's not done strategically.
Example:
Incorrect: "The goal is to quickly and efficiently complete the project, and to carefully analyze the results."
* Problem: The infinitive phrases "to quickly and efficiently complete" and "to carefully analyze" are not parallel. The adverb "carefully" modifies "analyze," while "quickly and efficiently" modify "complete."
Correct: "The goal is to complete the project quickly and efficiently and to analyze the results carefully."
* Solution: By moving the adverbs to their respective verbs, we achieve parallel structure.
In short, focus on creating parallel structure first, and then consider whether splitting infinitives is necessary to improve clarity or style. Don't use splitting infinitives as a way to fix parallel structure issues.