Similarities:

1. Both academic and professional writing share the same basic purpose, which is to communicate information and ideas effectively and efficiently.

2. Both genres share a certain level of formality in their writing style, which demands proper grammar, sentence construction, and language use.

3. Both academic and professional writing are associated with specialized subjects and disciplines that require extensive research, analysis, and critical thinking.

Differences:

1. Professional writing is typically aimed at a specific audience, such as clients, customers, or colleagues, while academic writing is aimed at a broader audience of researchers or scholars.

2. Professional writing tends to be more persuasive in tone, while academic writing is more objective, analytical, and often more heavily cited.

3. The style of academic writing is more formal and more technical than professional writing. Additionally, academic writing employs academic conventions such as citation and referencing.

4. Academic writing is designed to educate, inform, and persuade. Professional writing, on the other hand, is often designed to persuade or to sell a product or service.