You ask an LLM to do it. Not sarcasm, they’re quite good at ranking the quality of content already and you could certainly fine tune one to be very good at it. You also don’t need to filter out all of the machine written content, only the low quality and redundant samples. You have to do this anyways with human generated writing.
I just tried asking ChatGPT to rate various BBC and NYT articles out of 10, and it consistently gave all of them a 7 or 8. Then I tried today's featured Wikipedia article, which got a 7, which it revised to an 8 after regenerating the respose. Then I tried the same but with BuzzFeeds hilariously shallow AI-generated travel articles[1] and it also gave those 7 or 8 every time. Then I asked ChatGPT to write a review of the iPhone 20, fed it back, and it gave itself a 7.5 out of 10.
I personally give this experiment a 7, maybe 8 out of 10.
ChatGPT has a giant system prompt that you have no control over. Try using Llama and create a system prompt with clear instructions and examples. If you were going to use a model in a production system you would also want to either fine tune it or train a BERT-like model as a classifier that just outputs a score. Maybe even more than one for ranking along different dimensions.
