The phrase "a decisive question" is correct and usable in written English.
It can be used when referring to a question that is critical or pivotal in determining an outcome or making a decision.
Example: "The committee faced a decisive question regarding the future of the project that would impact all stakeholders involved."
Alternatives: "a critical question" or "a pivotal question".
There's little about reform of the financial authorities and that is a very decisive question, because whether you set the corporate tax at 26% or 28% is in the end not nearly so important as whether you actually collect it.
but you have also ensured that the referendum next year will give the Scottish people a clear and decisive question on which to cast their vote.
"It is at least rational to put to the Scottish people: would it be better to have a more fair and decisive question put earlier?" He said Scotland was better off inside the UK.
But … I think what the Scottish people deserve is a fair, clear and decisive question". Scotland's deputy first minister, Nicola Sturgeon, told BBC Radio 4's Today programme Cameron's move represented a "blatant attempt to interfere in a decision that's rightly one for the Scottish people".
Mr Cameron told Sky News he wanted to resolve that "legal uncertainty" and wanted to work with the Scottish government to give the people of Scotland the option of "a fair and more decisive question", put earlier rather than later.
"In Europe, the decisive question is whether a merger will create or strengthen a position of market dominance.
The universe of conceivable compounds is almost infinite, therefore, the decisive question arises: where is a biologically validated starting point in structural space from which to build a compound library to be found?
The decisive question: what African country is building a new capital called Oyala in the rain forest, 65 miles east of the current capital, Bala?
Again, the decisive question is not to what extent the IPCC directly influenced policy decisions, but rather to what extent the IPCC helped facilitate deliberative policy learning in these cases.
"As long as the decisive question is sentiments, you don't have to ask any of the practical questions".
