Thread by @cecilejanssens

How do you recognize good research ideas that are worth your time and effort? And how do you evaluate whether the hypotheses of others make sense? Here is my take:
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Doing science means following the scientific method. The hypotheses we choose to investigate (also in hypothesis-free research) follows from the rigor of our background research and a process that is called inductive reasoning.

Through inductive reasoning, we specify hypotheses based on earlier observations and studies. We build a case for our hypothesis.

This case can be strong or weak. The case is cogent if we can rely on the premises to be true. A case can be made stronger with more supporting evidence from more background research, and weaker e.g., if new evidence contradicts.

Let's take an example:
There was a day when the relationship between smoking and lung cancer was not yet established. Doll and Hill started their data collection in 1947. Why did they think they had a strong case to expect a relationship?

This is how they justify their case in the introduction of their paper: a trend in lung cancer mortality, for which they ruled out some alternative explanations, a trend in smoking, and some anecdotal observations. A pretty strong case.

Here's a recent example of a diet aimed to improve prostate cancer progression. Does this introduction make a strong case that the diet is likely to deliver? What other premises do we need to make it a strong case?

Here are examples of evidence that are essential to justify that the diet might work (also the study protocol paper that they cite did not provide this evidence).
With a weak case, an RCT is more likely to show no benefit of the intervention (the diet didn't work).

In the introduction of a paper, authors provide pieces of evidence to justify their research aims or hypotheses. Thinking about the missing premises helps evaluating the strength of their case.
When writing the introduction of your own papers, think about making your case.

So much can be investigated, but not everything is going to make a difference.

If you want your study/intervention/etc to deliver, make a strong case for it. Before you start the work.

Thinking takes time, being on the wrong track takes longer.
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