One must be tested on the book that they finished reading.
A test that checks a reader in different areas. Asking the reader about the characters in the book,the relationship between the characters ,their employment ,vocabulary knowledge,idioms.
The timeline of events taking places.
If a reader passes with the satisfactory score then only it could be considered that the person has actually read the book.
Otherwise skimming through the book doesn’t return anything positive ,they are better off not reading a book. Reading a book in such a sloppy and flippant manner shows that reader just wants to feel good by feeling the sense of belonging to the group of other wise readers.