Describe where the end result is the measure and not the measure to get there

Question

I am trying to get a word for an approach or characteristic where you have many subjective approaches or biased views but because they are all subjective, the most suitable one can only be measured by the end result and not some other measure of suitability. i.e. out of the 3 subjective approaches the one will be shown to be more effective once you compare the objective results

Examples

The school assignment is to write an essay. Sally has an incredible vocabulary and is sure she will get the best mark because of it. John has an very strong imagination. Sally tells John he can't possibly get a better mark than her because of her advantage. After receiving results John gets the top mark.

John has a [...] approach.

Other examples

Two school football teams play against each other. The one team is favored because their players are much bigger and athletic. However the other team ends up winning because they played more strategically.

and

Researcher A, B,C gets a grant for 1 million USD dollars each to help prevent patients from dying from the HIV virus. Researcher A is an expert in research of preventing the virus from infecting people. Researcher B has the most research in treating patients symptoms once infected. Researcher C has the most research in stopping the virus from spreading in the human body. After 1 year Researcher B's research is found to save the most lives.

and

Doctor A believes his 30 year of prior experience will help him diagnose the patient correctly. Doctor B believes his intuition will help him diagnose the patient accurately. Both disagreed on each others diagnosis. Doctor B was found to be correct. Doctor B is [...]

and

The tortoise and the hare are in a race. The tortoise wins due to a [different] approach

This is not goal orientated as everyone was goal driven. Same argument for go-getter.

Not longshot as although the others might be favored, each person believes their uniqueness to solve the approach is correct.

Not novel approach as it just indicates is is means different where I want to say different and proven correct

Not End result in mind as all had the end result in mind.

Answer 1

In all your examples, any one of the proposed strategies could have succeeded. In retrospect, only one of them did. The only thing you can say is that the winning approach was empirically more successful than the others.

empirical
Relying on or derived from observation or experiment: empirical results that supported the hypothesis.
American Heritage® Dictionary

Note especially the #2 definition below:

empirical
1 : originating in or based on observation or experience <empirical data>
2 : relying on experience or observation alone often without due regard for system and theory <an empirical basis for the theory>
3 : capable of being verified or disproved by observation or experiment <empirical laws>
http://www.merriam-webster.com/dictionary/empirical

Answer 2

You could say that they use an unconventional [MW] approach,

very different from the things that are used or accepted by most people

which is validated ex post [MW]

based on knowledge and retrospection and being essentially objective and factual

Answer 3

You are describing the philosophical notion of consequentialism, frequently stated colloquially as "the ends justify the means." In this way of viewing the world, all actions should be judged solely by their ultimate outcome, and not at all by intermediate steps taken to arrive at that outcome. Dictionary.com shows that the variant consequentialist exists. Of course, the idea is not without controversy.

It isn't a perfect fit for you examples. When I read back "John has a consequentialist approach" or "The turtle wins because of consequentialism" neither sounds quite right. However, I think a slight paraphrasing might work.

Answer 4

Not quite right, but I'll put it out there. How about tried-and-true?

M-W:

tried-and-true: proved good, desirable, or feasible : shown or known to be worthy

Your example:

John has a tried-and-true approach.

Tried-and-true conveys the sense of having been verified empirically, as suggested by @Michael.Hor257k.

Answer 5

In your examples, somebody succeeds against all odds. While it doesn't describe the approach, the result is called an upset [Wikipedia]

In the case where an underdog wins, the outcome is an upset.