open question

British  

noun

1. a matter which is undecided

2. a question that cannot be answered with a yes or no but requires a developed answer

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open question Idioms  

1. An unresolved issue, one that has not been finally determined. For example, Whether the town should pave all the unpaved roads remains an open question. In the mid-1800s this term acquired a specific meaning in the British Parliament, that is, “an issue on which members may vote independently, without respect to their party affiliation.”

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Example Sentences

As part of this, we are tackling the open question of how centromeres assemble the kinetochore.

From Science Daily

Whether an incoming Fed chair philosophically skeptical of reactive policymaking will be receptive to more data inputs remains an open question.

From Barron's

It is an open question whether many Kurds will answer the call.

From Slate

It is also an open question whether the shakeup will lead to a new direction in policy at the Department of Homeland Security.

From BBC

But it can also be viewed as a moral responsibility for the US to see it through, though it's an open question as to how much that would sway a president who believes there is always a deal to be done.

From BBC