prior to the 30-million-word-gap study, extensive research had noted strong institutional variation in student success on standardized tests. the initial attention to achievement gap started with a 1966 publication from the u.s. department of education titled "equality of educational opportunity." the publication begins the onset of achievement gap by acknowledging that there is a great disparity within educational outcomes as a result of inequitable institutions, especially those that were not seen as part of the purview of schools such as cultural, socioeconomic, and linguistic realities of students at home. the national assessment of educational progress (naep) had further been used to census information that various studies used to show achievement gaps across a number of demographics. the idea of equity in education had also given rise to similar gap discourse around the world.