Two-thirds of all Philadelphia third graders cannot read at grade level, a marker researchers say can be a make-or-break in determining if students succeed in school or make it to 12th-grade graduation. For the last three years, an early literacy effort known as Read by 4th has aimed to change that, with over 100 philanthropic organizations and partners large and small pouring tens of millions of dollars into a citywide effort to double the number of kids who hit that mark before fourth grade.