Tongue-in-Cheek Answer: Let’s try to patent it and see!
Humor aside, a knowledgeable patent professional will rarely — if ever — definitively answer this question (and even then only if it is clearly un-patentable). There are a number of factors that affect the patentability of an invention — what is claimed, what has already become public knowledge, quality of the application filed, Examiner’s personal experience and perception of the application, even patent prosecution budget, and much more.
However, while these factors make a definitive certainty about the patentability of an invention impossible, they can also be thoughtfully evaluated and compared to give an educated guess at the probability that an invention is patentable.
Questions to ask include:
- What field is the invention in?
- What is the improvement over the prior art?
- How close is the prior art?
- What has already been disclosed?
- What problem did this solve?
- How much did the solution save people?
- What other solutions have been developed for this problem?
- How close is this solution to similar solutions in other fields?
Your patent professional can help you step through these questions — and others — and evaluate the possibility of patentability, and weigh it against your potential ROI on any patent(s) that may be issued.