Best overview: Baradaran et al 2020 - A Survey on Machine Reading Comprehension Systems.
Span-based QA datasets like SQuAD require that the answer span is contiguous. Multi-Span QA relaxes this restriction so that questions like “What are the type of Turing Machines?” can be answered with multiple spans from the context passage.
See the related work in Yue 2022 and Yue 2022, and also Arafat Sultan's publications on QA.
See also Question Generation.
See Rogers et al 2022 - QA Dataset Explosion. See also NLP Progress - Question Answering and Geetanjali's QA Datasets Spreadsheet
