The Thirty Million Word Gap


In 1995, Betty Hart and Todd Risley conducted a landmark study using 42 families of a variety of socio-economic backgrounds.  The study was to help determine the significant effects of language and vocabulary in the home on a child's later success in life.  Their work was performed over a 4 year period, and they started with families who had children at 7 months and followed them through to the age of 3.  The differences of parent-child interactions were quite vast and determined that children of higher income families were exposed to thirty million more words by the age of 4, than children living in poverty (welfare).

Some of the results were the following:

  • Children from low income families heard about 616 words per hour
  • Children from working class families heard about 1251 words per hour
  • Children from professional families heard about 2153 words per hour
  • Children from higher income families heard many more words of praise compared to those of low income families

It was also found that the accomplishments of a child at the age of 3, with regards to their language and literacy development, were a clear indicator of that child's performance by the ages of 9 or 10 years.

We now know that what is equally important as the number of words a child hears, is also the quality of the words heard. Positive words of praise and a rich vocabulary go a long way to improving language development.

The study was able to prove that what happens in a child's home is the key to early childhood success.

Learn more about this study:

The Thirty Million Word Gap - Rice University Center for Education

The Early Catastrophe: The 30 Million Word Gap by Age 3

Dr. Risley's Speaks about Meaningful Differences


Target Age
0-3 , 3-6 , 6-12
2000 Words to Grow , Current Research