Every ERP migration produces a mapping document. Source field on the left, target field on the right, a transform rule in the middle, hundreds of rows of it. And on most programs, that document is what the experts are asked to review. They approve a spreadsheet that describes the data instead of the data itself.
The problem is that a mapping row can be perfectly reasonable and still produce a wrong column. The unit-of-measure crosswalk misses a value that only appears in one plant. The date field carries a status code in a corner of the source nobody sampled. None of that is visible in the mapping document, so it surfaces at the mock load, weeks later, as a defect list. The fix gets applied by hand, the next extract arrives, and the same defect comes back because the fix lived in someone's working file.
So we inverted the order of operations. Generate the actual load file first, in the target system's own template, from the real extracts. Then put that file in front of the experts. A reviewer looking at real rows in target format does not have to imagine what the mapping will produce. They are looking at it. They approve or reject each column on evidence, and every rejection turns into a rule that regenerates the file.
The compounding effect is the part we did not fully anticipate. Because every column carries a fingerprint of its mapping, an approval travels across regenerations for as long as that mapping holds. When a fresh extract lands and the file rebuilds, the columns whose mapping did not change keep their verdicts. On a typical re-release, roughly 77% of columns need no re-review. That number is observed on a live engagement, typical, not guaranteed, and it is the difference between review that shrinks each cycle and review that starts over each cycle.
One boundary keeps the whole thing honest: the platform cannot release a file. Release is a human verdict, enforced in the platform, and the generated file only reaches the load team after it clears the people who own the data. The target ERP's built-in loader still does the physical load. What changed is what arrives at that loader: a file that has already been reviewed the way it should have been all along, column by column, on real data.
That is the method. The rest of this site describes the machinery around it; this note is why the machinery points the direction it does.