The Bible's accuracy is determined less by historical gauges than it is by Revelation Knowledge received by the reader. Without a revelation from God, no one can understand a fact beyond a subjective, temporary meaning. Once a person has seen eternal life as a reality - one that's been made convincingly clear to him - all other details are meaningless. That person will then judge the "truth" in light of its relevance to living eternally with God. Someone without that understanding will judge "truth" by its ability to support his ego, provide momentary comfort, or social acceptance: because those things are the highest realities in his world.
Occasionally you may hear that a segment of the Bible's text is being questioned: someone finds a story in another ancient text that's similar to one in the Bible; or the year that's ascribed to a particular book isn't verifiable. So what do things like this mean to the Believer? For one, it will reveal the character the Believer. For him, the things that gave him a revelation of God and his own eternal existence will be the litmus test for any "truth". The things that lead the Believer to that great awareness of reality will be the Final Word on any issue of "validity". Even if a transcription somewhere in the Bible were technically imperfect: The sum total of the book leads the reader to the place he needs to be for personal contact with God. From that moment onward, the individual receives revelations from God that clarify any questions he may have about life.
Matthew 16:13-18 - When Jesus came into the coasts of Caesarea Philippi, he asked his disciples, "Whom do men say that I am?" And they said, "Some say that you are John the Baptist, some say Elijah, and others say Jeremiah, or one of the prophets." Jesus said to them, "But who do you say that I am?" And Simon Peter answered, "You are the Anointed One, the Son of the living God." And Jesus answered him, saying, "Blessed are you Simon Bar Jonah, for it was not flesh and blood that revealed this to you, but my father who is in heaven. And I also say to you that you are Petros, [a portion of rock] [4074 in the Greek dictionary of Strong's Concordance], and upon this petra [massive rock formation] , I will build my church, and the gates of hell will not prove stronger than it."
Here Peter has knowledge revealed to him from God the father. It was certain and clear in Peter's spirit and mind - even though the "wise" men of that time could not have given him this revelation. He was "blessed", or empowered by God, because he had received an avenue of power from God that went "outside the box" of knowledge available in the physical earth. Revelation Knowledge is a blessing that gives the Believer a channel of understanding directly from God to the Believer's own spirit - something that the world cannot corrupt with its lifeless opinions.
This is the petra, or massive rock formation (e.g., a canyon), that Jesus calls the foundation of the church. We believe because we know. We know God is real because God has revealed it to us personally, in those times when our spirit was "plugged into" God's Spirit. This is why Jesus called Peter "petros", a piece of rock, because Peter, by receiving that revelation from God, was a part of that massive rock (of Revelation Knowledge) that the church is built upon. Our belief is not built upon church history. Our belief is not based on fear, or nagging by church officials, or wishful thinking.
Our belief is based on direct and personal contact with God - and it grows continually by revelations we receive as we maintain our direct contact with Him.
This Revelation Knowledge makes the Bible real and understandable to us. It is the Spirit of God who reveals the meaning behind the words - and He does it in a way that gives us evidence that is more substantial than anything we see or hear in this physical earth. Those who have a difficult time understanding the Bible - people without direct contact with God - are in bondage to the view that "truth" has to be proven by comparing it to something in the limited physical world. When the Bible speaks of things that are outside the realm of ordinary physical phenomena, the unspiritual mind is only capable of seeing it as a "fantasy". The natural brain, separated from one's spirit, can only comprehend the dying and decaying world of our five senses.
But we are spiritual beings. We need more information than can be gotten from the physical world in order to be complete. We were not designed for this limited-duration world. If we were, unspiritual human beings wouldn't have any discomfort with the concept of their mortality. If we were naturally designed this way, our instincts would see comfort in physical death just as it would in eating, sex, and any other physical event that is "natural". But physical death isn't in our original design, and deep down we know that - we just can't figure out "why" with our limited intellects. We are spirits and we have to exist eternally (in one way or another: in heaven or hell). When God created man, man had no death in him. When man violated his covenant with God, he entered into agreement with Satan, which then ushered in death to the world. It was a curse - not a naturally-occurring phenomenon. It is a criminal intrusion from an anti-God, anti-life force. The sacrifice of Jesus took that authority away from the devil finally, and put the Believers into joint authority with Jesus over the devil and the events of the earth: "I [Jesus] ...have the keys of hell and death." - Revelation 1:18.
So, to the worldly mind, the study of science and human history must be "objective" and neutral. But this "neutrality" causes us to view the present world as the "standard" by which all other things are compared and proven. Without the Revelation Knowledge that Peter was blessed with in Matthew 16:17, man is incapable of understanding the full scope of the facts that govern our existence as spiritual beings. And because of this, life will always be a mystery to the physical mind of man.
This is also the reason why the Bible will always remain a mystery to the unspiritual, ungodly man: it will be forever beyond the limits of "intellectual" comprehension. It's like a 2-dimensional photograph trying to display a 3-dimensional world. WE WILL NEVER COMPREHEND ETERNAL LIFE BY STUDYING THE PHYSICAL EARTH, simply because we are eternal and the earth is not. That alone proves that science is looking for water in a dry well when it questions metaphysical things. We'll never find evidence of eternal life by looking at the dying world.
The accuracy of the Bible is illuminated by that massive rock foundation of Revelation Knowledge from God the father. When we open our spirits to His Spirit, knowledge that's beyond our intellects' limitations allows us to finally make sense of it all. It also lets us see that all our intellectual strivings could never bring about this level of understanding no matter how long we worked at it.