I came across this phrase when I was reading a research paper. Here's a quote from the abstract:
I find that the urban-rural gap accounts for 40% of mean country inequality and much of its cross-country variation.
After doing some research on the internet, I've found out that "urban-rural gap" is frequently used on Chinese and Taiwanese news sites. Personally, I've never seen this wording before so I'm not sure if this is a direct translation from Chinese. Is this a proper English term for a disparity between urban and rural areas or just an artifact of a word-for-word translation?