[stevenmays]

The textbook was more advanced, but how was well was the information retained? Perhaps most fifth graders are retaining information better now with books more suited to them?

Literacy rates have increased throughout the years: https://nces.ed.gov/naal/lit_history.asp

[tracker1]

If it was replicated/repeated for the next several years, I'd imagine the retention was relatively good. Likely as good or better for most people than today.

[EthanHeilman]

Far fewer people in the past graduated Highschool as well. For instance only 50% of students graduated Highschool in the 1950s. As of 2008 the Highschool graduation rate is 80%.

[tracker1]

So, why lower the bar? A "C" is a passing grade by all accounts... lowering the bar only serves to hold back those able to do better.