The phrase "a significant doubt" is correct and usable in written English.
It can be used when expressing a strong uncertainty or lack of confidence about something.
Example: "There is a significant doubt regarding the accuracy of the data presented in the report."
Alternatives: "a considerable doubt" or "a serious doubt".
John Appleby, the King's Fund's chief economist, said the results indicated that with many trusts facing "very tough cost improvement targets … there must be a significant doubt about whether many of these targets will be met".
Vincent Kompany will miss at least two games for Manchester City and is a significant doubt for the game against AS Roma that will determine whether the club make it through to the Champions league knockout stages.
This leaves London without financial backing and also, almost certainly, without a home ground for next season, with Varney adding that Charlton's plan to re-lay the Valley pitch "means that there is a significant doubt whether we will be able to stage rugby league in 2002".
In particular, in cases of divergence they create a significant doubt about whether we can learn from them at all for decision-making processes.
As a consequence, there is significant doubt about the effectiveness of the whistleblower law to protect health and care workers on Nauru and in PNG.
A report by the Congressional Research Service this month said that the fighting in Basra — which ended after Iran took credit for brokering a cease-fire — "cast significant doubt on the effectiveness of the U.S. counter-measures" against the Iranian efforts.
But now, a new analysis casts significant doubt on the previous weight estimate.
"Ambac's ability to raise sufficient capital to avoid a downgrade is now in significant doubt," said CreditSights analyst Rob Haines in a research note Thursday.
WASHINGTON — One week after President Obama demanded that Col. Muammar el-Qaddafi cede power in Libya, the president's top intelligence official predicted on Thursday, "over the longer term, that the regime will prevail" in Libya's civil war, an assessment that cast significant doubt on efforts so far by the NATO allies to drive him from power.
In European Mission to Moscow At an informal meeting in France by European foreign ministers, there was significant doubt that a diplomatic mission to Moscow in response to the crisis in Georgia would produce substantial, concrete results.
This indicated "a material uncertainty that may cast significant doubt on the group's ability to continue as a going concern", BIH said.
