For our next step, I compared the gospels to the Torah. That is, I compared the combined texts of Matthew, Mark, Luke, and John to the combined texts of Genesis, Exodus, Leviticus, Numbers, and Deuteronomy.
The Short Version of the Results
Shared Word Estimate (12/46) = 26% or (11/46) = 24%, depending on whether or not we recognize a match between the word "Israelites" in the Torah and the word "Jews" in the New Testament. We're working with differences in language, history, and culture; you could argue that decision either way. So the results are presented both ways.
Shared Emphasis Estimate: 25% or 24%, again depending on whether "Israelites" and "Jews" are considered a match.
Different than Comparisons within the New Testament
Between the Torah and the Biblical Gospels, we have a match on emphasis that is roughly 24-25%. It is only slightly less than the match rate between Paul's letter to the Romans and the Gospel of Luke, though again far less than matches among the gospels.
Many of the differences are so expected that I will mention them without much comment. While the gospels discuss Jesus and his disciples, the Torah discusses the patriarchs and Moses. The context is different: the gospels have "Jerusalem" or the "house", while the Torah has "Egypt" and "tent". The language of ancient ritual sacrifice has a set of words that are common in the Torah but not in the gospels: offering, altar, sin, blood, fire, holy, gold, burnt, grain, animal. ("Sin" is at the low end of common words in the individual gospels of Matthew and John, but does not make the common words list of the combined gospels. The words specific to the ancient sacrifices are not common in any of the gospels.)
When we take a closer look at the areas that are in common, we see most of the shared emphasis coming from the words "God" and "Lord", "father" and "son", "man" and "people" -- and "priests". Most of those matches call for a closer look and further thought.
If "Lord" generally means "God" in the Torah, but sometimes "God" and sometimes "Jesus" in the gospels, then do those words mean the same thing and should those words really match? A Christian might say yes, a Jew might say no, and both might agree that this difference is critical. It is important not to take the mathematical studies in a way that depends on someone's personal viewpoint; it defeats the purpose of a mathematical review. Someone who is an analyst first might note that both documents have an emphasis on "Lord" as an important figure, while allowing that the different authors may have different ideas about who exactly the Lord is. And that should be a fair observation from anyone's point of view.
If "father" and "son" are used in numerous accounts of family and genealogies in the Torah, does it really count that they are also common words in the gospels, where the words might mean God and Jesus? Then again, the gospels also contain two Jewish-style genealogies. Never mind for the moment whether they match each other or whether you believe either of them; the same could be said of other genealogies. The point for a computerized word comparison is not whether you can post the family tree on a genealogy site; the point is that some of the structure of the gospels of Matthew and Luke -- the structure that includes a genealogy -- is part of a convention that goes back to the Torah. So the commonness of "father" and "son" language in the gospels is not entirely foreign to the Torah, and has some of its roots in the Torah. God is also referred to as "father" in the Torah (see Deuteronomy 32:6, though I have certainly not yet made a complete check to find all the references.) So the references to God as "father" in the gospels are not completely unheard of in the Torah, and may in some part trace back to a tradition found in the Torah. For matches like this, as they say, the truth is complicated.
This comparison also brings to light some more features of the tools being used. The more different two documents are, the more questions that arise about even the matches that are found. Here the gospels are written in a culture that was deliberately trying to live according to the Torah and pattern their religious thoughts after the Torah, so the gospels and the Torah were bound to have some similarities. The similarity of the gospels to the Torah was roughly on the same scale as a similarity of Luke to the letter to the Romans, though for different reasons.
As this series goes on with a few more examples, we will likely see a few comparisons that show only a slight relationship if any. When documents are largely different, there is another question that comes to light: are the documents similar enough to warrant a comparison? I won't presume to answer that question so soon, with only a few comparisons completed so far. It may be useful to look at two completely unrelated documents at some point to see if the analysis can detect that that lack of relationship.