What is a 'gap in the literature' and how to find it

[WillFaber]

My research methods professor keeps saying "find the gap in the literature" for our proposal and I'm just sitting here like... sir, the literature is VAST. There are no gaps. It's all full.

What I THINK it means:

Like, something that hasn't been studied yet? A question nobody asked? But how do I know what nobody asked?? I'm not omniscient??

What my professor says:

"The gap is where your research fits into the existing conversation. You're not just repeating what others said—you're adding something new."

Okay but HOW do I find that??

My current strategy:

1. Read 5-10 recent articles on my topic (documentary ethics)
2. Look at their "future research" sections (apparently this is KEY)
3. See if multiple articles mention the same missing thing
4. That missing thing = the gap?? maybe??

Example I found:

Lots of articles talk about ethics in documentary FILMING. But almost none talk about ethics in documentary EDITING (like, is manipulating footage in post unethical??). Is that a gap?? It feels too small but maybe that's the point??

Questions for the pros:

• How do you know if a gap is worth studying?
• Can a gap be too small? Too big?
• What if I think I found a gap but actually it's been studied and I just missed it??
• How many sources do I need to read before I can confidently say "there's a gap"?

I'm overthinking this probably. That's my brand.

Drop your gap-finding tips below. I need a roadmap. A treasure map. An archaeological dig site but for ideas.

Thanks!!