The hardest thing for any international rugby side to do is accurately measure the intensity of their collective desire and gauge just what each individual is prepared to do to play their part.
Test rugby is like the Death Zone on Everest, it can't be endured successfully unless thosewho go there are prepared to push themselves beyond where they consider their limits to be.
And for humans to push beyond their perceived limits they have to first know what those limits are and have a deep and unflinching understanding of why they want to break them.
No one gets lucky in hostile environments and any corners that have been cut, doubts that have lingered or uncertainties that pervade will be ruthlessly exposed.
Clearly, since the end of last year and in the series against Ireland, the All Blacks found they weren't able to operate as they would have liked in the Death Zone.
And like all climbers who have tried but failed to summit the world's highest mountain, they are now back at base camp, digging around in the deepest parts of their soul trying to determine the root cause of this sustained period of underperformance where the losses have piled up.
The outcome so far has been to dispense with the coaching services of John Plumtree and Brad Mooar and bring in Jason Ryan from the Crusaders.
With Joe Schmidt also now taking up the selector/analyst role he agreed to late last year and Blues head coach Leon MacDonald being courted to join as attack coach, the All Blacks have made positive changes to address the shortcomings which they have identified in their set-up.
The question, however, that will inevitably be continually asked in the next few weeks and possibly months, is whether they have gone far enough with the changes they have made and whether they can now be confident of surviving in the Death Zone.
What we don't know and won't know until the All Blacks face South Africa, is whether they have found answers to the two fundamental questions of knowing where their individual and limits sit and why they are collectively willing to do everything they can to push beyond them.
It's the second question which is most important and just as mountaineers must first ask and always understand why they want to climb Everest, the All Blacks need to be connected to a higher purpose with a clearly defined sense of who they are and what they want to be.
And it's only when they have a unified answer to that, will they have a means to accurately measure the intensity and integrity of their preparation as they will be able to assess whether their standards in all aspects of their work are aligned with their ambition.
The All Blacks need a defined means to hold themselves truly accountable – and the best teams in their history have done that through the strength of their connection to their vision statement.
There's no better example than the All Blacks of 2012-2015. When Steve Hansen took over as head coach, he brought his leadership team to Christchurch – players such as Richie McCaw, Dan Carter, Kieran Read and Conrad Smith – and told them that winning the World Cup meant diddley squat in his eyes.
He wanted that All Blacks group to be the most dominant team in the history of rugby and that everything they did would be done with that goal in mind.
That meant they trained as they felt the most dominant team in history needed to train and they conducted themselves off the field as their ambition dictated.
The environment was border-line hostile, with players holding each other genuinely accountable and everyone, even the captain, harbouring doubt about whether they would be picked each week.
It was a hard, uncompromising workplace which tended to wheedle out those who couldn't go deep enough within themselves to give all that was needed.
Essentially, that All Blacks side permanently lived in the Death Zone – where they were always uncomfortable and on the edge of their physical and mental limits, if not beyond.
Only those who have experienced life within the team these past few years will know whether the current environment has forced them to live outside of their comfort zone in the same way and driven the same culture of raw honesty about the depth of their preparation.
The arrival of Ryan and Schmidt will bring fresh eyes to ask new questions and the hope is that will force everyone in the set-up – players, coaches and management – to deliver higher standards, the sort that they will need if they are to survive life in the Death Zone.