From Kids Can Recover From Missing Even Quite A Lot Of School by Alexander Scott.  As usual, a very good piece presenting the balance of evidence and allowing the best arguments and the better data on both positions.  The answer is that you can miss a lot of structured education, do well and have no impact on your future outcomes (health, income, etc.)  

I did like this paragraph especially, simply because it matches the real world experience of many friends.  

(my own experience with these standardized tests is that eg my school’s social studies courses would move leisurely through the Native American and colonial era, get distracted talking about How Bad Slavery Was, and then a week before the standardized test go into “ohmigod we’re supposed to be at the 1950s now fuck fuck fuck Grant Hayes Garfield Arthur Cleveland Harrison Cleveland McKinley World War One World War Two labor unions Japanese internment ok good luck!” mode. If the day you miss is during that period, I can definitely believe you do worse on test questions about the McKinley administration one week later.)

My wife, educated in the public school system in the South excused away the paucity of her knowledge of modern history by claiming that every year, their history class started with Columbus and pretty much ended at the Civil War.  Year after year.  

I long thought this to be a joke argument but subsequently discovered it was true.