Can an unpromising research project be recognised in advance?

How can a researcher recognise a fruitless project before going deeply into it?

There is no sure way to know in advance; the investigation has to show whether the idea bears fruit.

A promising question does not guarantee a productive investigation. Following the evidence may reveal why earlier researchers did not pursue the subject. The potential result remains uncertain until the work produces something useful, so there is no dependable shortcut for identifying every dead end beforehand.