What does an objective research project even look like? How do we even define 'regret'?
That is exactly what clinical trial design is for and why it involves multiple stakeholders. It's also why clinical trials are pre-registered so there can be no rannygazoo, changes of mind, p-hacking, or conveniently forgetting to include some outcomes for publication.
If anyone is interested in this, or evidence-based medicine and how it's evaluated, I strongly recommend the book, Testing Treatments, that is free to download and interactive, the audiobook is also a free download.
https://www.testingtreatments.org/
The Cochrane Handbook is the formal guide to the methods, processes, and tools for systematic reviews. It explains types of clinical trial design along the way.
https://training.cochrane.org/handbook/current/part-1