In For long-term savings: Short-term Bond ETFs vs High-interest Savings Accounts, I specifically asked for academic empirical evidence.
Note that the question has now been deleted by the Community user under the standard cleanup policies for old, closed questions.
It described competing strategies for investing in short-term bond ETFs versus high-interest savings accounts and ended by asking:
But what do the empirical evidence and academic studies prove? Which is recommended?
"Primarily opinion-based" is often a judgement call - some questions do require some degree of subjective judgement to answer, but still aren't primarily opinion-based. However I think this question does fall on the wrong side of the line.
It's unlikely that there will be clear cut empirical evidence or academic studies that prove anything. In the end any answer will be someone's opinion about which is better, even if an informed, academic opinion.
Another possible problem with the question is that it's inviting a list of academic resources, and list questions are discouraged on StackExchange.
I think it might be possible to ask a question about this area and keep it on-topic, perhaps by asking a more direct question that focuses on concrete trade-offs rather than asking which is better. For example, someone commented on your question:
Recommended for what? The two approaches trade different amounts of risk for different returns.
I think a question about the relative risks and returns of the two investments would be on-topic. The answers to such a question would be reasonably factual, rather than coming down to an explicit recommendation of one strategy over another.