1964 Topps coin scratched back
 

How do people look at the coin scratched back of these cards? I asked a few people and some say it doesn’t matter and it doesn’t detract from the grade. Others vehemently saw it’s an automatic EX condition card. I’m putting this set together in high grade and would like to know the consensus.

Do you mean how do the grading companies assess the scratch aways?

If so, I would look on eBay for as many graded 1964 cards as you can (sold auctions too), and examine the ones with back scans to see if you can detect a pattern. In other words, if PSA 7s and 8s have scratched backs, it most likely means they don't detract for it.

My personal view is that a significant amount of scratches on the back can't be NM.

I've yet to find a pictoral guide to grading topps coins. If anyone has a link to one, I'd be grateful for it.

I would agree with the ex folks.

Scratched is a damaged altered state card and not as it was fresh from pack. Much like 1980 hockey, scratching is an automatic downgrade. Not as devastating as separation of 1980 basketball but certainly a drop to ex.