What word fits the sentence: 'it was proven with great _______'? [closed]

The word I'm looking for would suggest that the thing in question was shown to be true even to the point of excess, and its veracity tested on multiple occasions or very publicly, so that there can be no residual doubt.

e.g.

'it was proven with great _______ that her methods were ineffective'

I've tried looking up synonyms for 'thoroughly' and 'excessively' which didn't turn it up. The word is right on the tip of my tongue and it's been bugging me for ages.

Solution 1:

Not exactly what you've asked for, but you could try either "it was demonstrated conclusively that her methods were ineffective" or "it was shown conclusively that her methods were ineffective".

Solution 2:

I would suggest "with great finality."

1 a : the character or condition of being final, settled, irrevocable, or complete

b : the condition of being at an ultimate point especially of development or authority

Solution 3:

Can you switch your word order?

It was thoroughly proven that her methods were ineffective.

It was exhaustively proven that her methods were ineffective.

It was rigorously proven that...

It was unequivocally proven that...

Or keeping your current word order, perhaps:

It was proven with great rigor that...
It was proven unequivocally that...

Solution 4:

Having a look at the COCA - I have a suspicion the word you are looking for is Certainty.

While there are not many entries, certainty is the only recurring phrasing linked to proven with and to me is a fairly common construct expressing what you describe.

proven with statistical certainty are uncommon

proven with absolute certainty

In your sample,

It was proven with great certainty that her methods were inneffective

Solution 5:

Credibility

Collins Dictionary:

If someone or something has credibility, people believe in them and trust them.

(Emphasis mine)

Lexico powered by Oxford:

The quality of being convincing or believable.

In this case, you could say:

It was proven with great credibility that her methods were ineffective