Okay, this is clearly a comment by someone who's never worked a low-tech job. You validate correct data-entry by testing samples.

I worked a job back in high school where they spent months editing Excel spreadsheets full of data only to pass the edits to me as handwritten changes to printed pages. The stacks of spreadsheet pages I was given were meters high.

Since the human-made edits met simple patterns, I was able to write Excel macros to describe and perform them. I finished a week worth of work in one hour. In my case, they saw me reading a book and got irate even though the work was done and correct. I was a contractor, so they just asked me to go home early and collect fewer hours. I got paid less for working faster.