An extracted table contains every number from the scanned page. It still gives the wrong answer because a value from one row has been attached to the label above it. Character recognition and table reconstruction are related tasks, but success at one does not prove success at the other.
Before using an OCR result in a calculation or automated workflow, inspect the relationships that make the numbers meaningful.
Trace one row all the way across
Choose a row containing a label, a quantity and a unit. Compare each extracted cell with the source image. Then check the row above and below it. A shifted boundary can create plausible values in every cell while assigning them to the wrong item.
Pay particular attention to merged headings, wrapped labels, blank cells, repeated headers and tables that continue onto another page. A blank is not always zero, and a dash may have a meaning defined in a note.
Use a deliberately awkward test page
Create a small fictional table containing a subtotal, a negative value, a decimal and a long row label. Keep the expected structured result separately. This gives you something more revealing than a page of evenly spaced positive integers.
Check whether the system preserves units and distinguishes a footnote marker from part of a number. If the source uses a different decimal convention, make that explicit in the validation rather than trusting a familiar-looking output.
Where the tool provides coordinates or links back to the source, use them to review uncertain cells. A confidence score can prioritise checking, but it cannot replace checking the structure that your downstream task relies on.
Keep corrections traceable
Record the original image, extraction version and any manual corrections. Do not silently overwrite a value without retaining why it changed. If the table feeds a consequential financial, clinical or operational decision, require an appropriate review before use.
Test the calculation only after validating the mapping. A perfectly implemented formula can produce a precise answer from the wrong row. The useful question is therefore not merely “Did it read 42?” but “Did it attach 42 to the right thing, in the right unit, under the right heading?”