"Play-based preschools and kindergartens show significantly better long-term outcomes, both academically and socially, than didactic and overly academic programs for young children. Yet false assumptions about the importance of learning discrete cognitive skills, such as decoding and phonics, at an early age have led many schools to adopt developmentally inappropriate practices in kindergarten."
This statement is included in a policy brief from The Alliance for Childhood. HERE is the complete brief.