Word for a decision made without any analysis?

Question

Is there a word for a decision that's already been made despite the relevant processes not having been followed / analysis done.

Foregone conclusion feels similar to what I'm after; but that implies that the facts are so obvious as to make the decision process moot; whilst I'm after a word for where the conclusion is based on one person's perspective without them having consulted relevant stakeholders / investigated the various options / collected evidence to support or dispute their arguments / etc.

Answer 1

The 'aiming more for something around the lack of inclusion of others' perspectives than the individual's haste of decision making' caveat put in the comment makes unilateral decision relevant:

unilateral [adjective]

1. (of an action or decision): performed by or affecting only one person, group, or country involved in a situation, without the agreement of another or the others.

[Oxford Languages; courtesy of Google] An example from the internet:

• ... he made a unilateral decision – without consulting the other director or shareholder – to shut down the corporation.

[Casetext; Callier v. Callier]

Answer 2

You might want snap decision, though that implies the absence not only of consultation and coordination with others, but also even of much reflection by the one person involved.