jury is still out, the - Phrases/Idioms
The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
No decision has been made; the public's opinion is not known. For example, As for a possible merger, the jury is still out, or The jury is still out on the new spring fashions. This expression alludes to the jury that decides a legal case. [Colloquial; mid-1900s]