Determining what is and is not a question of law can be difficult. There are questions of fact, questions of law, and questions of mixed fact and law. (Mixed counts as a question of law for the purposes of being appealable).
Often you can work backwards from the 'error' and map how the conclusion was arrived at. Identify each relevant step propelling the conclusion onwards. How is each step resolved:
- Is it a plainly apparent fact? i.e. the sky is blue.
- Is it an agreed fact? i.e. both parties agree it was daytime.
- Is it a contested fact? Then, the manner by which the fact is determined may be relevant. If there's unchallenged (but contradictory) evidence then it's a question of fact determined by the decision maker. If the evidence is challenged on legitimate grounds, then the acceptance of that evidence becomes a question of law. If it should not have been accepted, then that can change the outcome of fact.
- Is it a test or rule? Likely to be a question of law.
- Is it a factual assumption? It was nighttime in July, at which time of year there is usually frost, therefore the road was likely slippery. That's a question of fact.
- Is is a legal assumption? The defendant intended to commit breaking and entering because he was found with a balaclava, lockpicks, a bag marked with a big $, and sneakers, and it wasn't Halloween. The determination of intent is a question of law, but based on assumptions drawn from fact.