Is There Really a 30 Million-Word Gap?

  • 08 September, 2018

Teacher question:

I attended one of your recent presentations. You cited the Hart & Risley canard that there is a 30 million-word gap. Aren’t you aware that study has been rejected? There is no word gap. Poverty kids have as much language support as other kids.

Shanahan response:

Research can get things wrong.

That’s why researchers—unlike practitioners and policymakers—are usually so interested in the methods of a study. Study a problem one way, you get one answer. Study it another way, perhaps a different answer emerges. Try to understand why the two studies diverged and youstart to gain a deeper understanding of the problem.

That’s why I don’t like the term “findings” in research studies. “Results” is the more accurate term. Even with qualitative studies that my claim no results, just findings, because they only watch and record and don’t intervene… yet, how one observes and records can influence outcomes, so even those kinds of studies have results.

In the 1990s, Hart and Risley published a widely disseminated study in which they collected language data on 42 families (some of these were upper socioeconomic status, some  were working class, and some were families on welfare). Monthly over 2.5 years, they audiotaped young children’s (7-9 months to 3 years) language environments.

They found that children were spoken to much more often in the upper income households than in the poverty households, and extrapolating across the children’s waking hours, they concluded that there was a 30 million-word gap. Some kids were having a lot more language experience. The researchers measured other more qualitative aspects of these children’s language environments as well, but the 30 million words became a symbol or summary of the whole study -- which has been hugely influential of policy and research.

As the questioner above notes, recently there has been some new evidence on young children’s early language environments. This summer, Child Development, published an article by Sperry, Sperry, & Miller (2018). Basically, it concluded that there were big differences in home language environments, but that these were equally distributed across the different socioeconomic strata. Some kids were definitely hearing fewer words than others, but it wasn't necessarily the kids living in poverty.

That study got a lot of play because it claimed to be a replication of the original study (it included 42 families as well). However, it was so different from Hart & Risley’s investigation that I think replication is the wrong description. For example, the biggest differences in H&R’s results were between the high SES kids and those growing up on welfare—that’s where the 30 million-word gap came from (working class and welfare differences were both much lower in this variable than the well-to-do), and yet this new study didn’t include a higher income sample. That alone could explain the lack of differences reported by Sperry and company. 

In the original study, the researchers went to the houses with tape recorders and sat there for an hour each month. There has been great concern that placing a PhD in the households of low-income families like that might suppress language use. Let’s face it. Anyone observed like that might be inhibited (I think I would be—I imagine whispering), and some speculate that this would be especially true for low income/low education parents (and there is research suggesting that this kind of inhibition does take place). If that were the case, then the welfare moms may have spoken to their children less than usual just because they were being observed.

There are things that can be done to limit or reduce such reticence (like having observers stay longer so those being observed get used to their presence or making sure the observers are of the same race and gender as those being watched, etc.), and this new study made better use of such methods. Perhaps the original observation techniques discouraged talking in some families and encouraged it in others. If so, then one might conclude that Sperry and company are correct.

The problem with that conclusion is it assumes that the only study reporting a language gap was the Hart & Risley investigation.

However, Sperry et al. weren’t the only ones re-exploring these waters and some of those other studies also reported such a gap. In my opinion, the most rigorous study on this so far is one reported by Gilkerson, et al., in 2017. They used technology instead of potentially-intrusive observers and collected a whopping 49,765 hours of recording from 329 families (more than the Hart and Sperry investigations combined). That study reported a much smaller word gap than what Hart & Risley claimed, but unlike Sperry, et al. it did identify a sizable gap (and with a much larger population, studied much less intrusively and more thoroughly).

Gilkerson claimed “only” a 4 million-word gap between those highly educated, high SES parents and those much less educated low SES ones. Four million words ain’t chopped liver! Spread over two years (these kids were observed from age 2 to 4), it would be like hearing a 55 minute a day speech from mom (spoken at 100 wpm… which is slightly slower than conversational speech, which makes sense for talking to a 2-year-old). But let’s face it…. No matter how much money or education you have, no one is going to give a 55-minute speech to a baby. What there will be is a lot more parent-child interaction…literally more hours of daily conversation between parent and toddler.

Another critical difference is that the Sperry study included the presence of ambient language. That’s the language not spoken to the children themselves, but that was in their environment. If Aunt Edna is yacking away on her iPhone while young Egbert is playing nearby his language is getting real shot in the arm, according to the Sperry methodology.

Hart & Risley (and Gilkerson) only counted words spoken to the child. One reason Sperry’s team found no difference was because of the language emanating from the TV sets and fugitive background conversations of adults who were not speaken to the kids. But as Golinkoff et al. (2018) point out, the notion that ambient language has a big effect on language development (compared to language spoken directly to the child) has been rejected by direct study. Despite the methodological problems evident in the original Hart & Risley work, analyzing the language spoken to the children instead of what might have been overheard from the TV in the next room was not one of them.

Finally, it should be pointed out that studies have shown that early language differences matter in later reading performance (Golinkoff, et al., 2018; National Early Literacy Panel, 2008). And, that the specific children exposed to low language environments in the Hart & Risley study, when followed to school, were themselves found to be at a learning disadvantage when it came to reading (Hart & Risely, 2003).

What that all means is that there is good reason to believe that many young children are not receiving sufficient language learning support during the preschool years, and that this insufficiency is implicated in later reading problems. High education, high income families appear to be more able to provide this kind of early language support, than low education, low income families. And, it is possible to provide aid and encouragement to families that allows them to narrow this significant gap (no matter what its actual size may be) (National Early Literacy Panel, 2008).

The Hart & Risley study has been under fire and it is far from a perfect study. Nevertheless, the results of this body of research continue to suggest that what parents do in the home with their children matters educationally (which is why I was using the study in my presentation). Parents need to do more to support their children’s early language learning and parents living in poverty can use some help there. Despite the methodological limitations of the Hart & Risley study, environmental differences (as opposed to genetic ones) still seems to be the best explanation of why poverty kids are underprepared when reading instruction begins.


See what others have to say about this topic.

Harriett Janetos Sep 08, 2018 01:25 AM

This 2014 TED Talk by Stanford researcher Anne Fernald does an excellent job elaborating on your points about why talking to little kids matters. Couple this with Jamie Metsala's Lexical Restructuring Hypothesis, and we get an illuminating picture of what needs to happen 0-5 for children to be ready to read in kindergartenn.

Rachel Klingelhofer Sep 08, 2018 09:41 PM

I suspect that part of the reason the conflicting research results have sparked so much (often heated) discussion is because of concerns about how families living in poverty are viewed by our society, particularly with respect to their parenting. I appreciate this question and this post that helps us think and talk about those results. However, I would like to suggest that the use in both the question and the response of the phrase “poverty kids” is problematic, and symptomatic of the positioning of families living in the lowest income brackets in our country. That way of talking about people is (rightly, I argue) troubling so many of us.

Tim Shanahan Sep 09, 2018 03:03 AM

Rachel— sorry that such language upsets you. Having grown up in poverty myself it doesn’t bother me at all, anymore than referring to me as male, Jewish, middle class, educated, etc. would today. I think trying to police the language so that we can’t point out that some children are more disadvantaged than others and that such disadvantage has terrible consequences is more problematic than the improvement that you imagine such policing provides.


Tory Callahan Sep 09, 2018 12:28 PM

Dr. Shanahan:
Thanks for insights on the language gap and its role in underachievement, including reading.
It's a tough time to try to help children who may most need it since it's shameful to define who we may be talking about. How do we develop more effective practices specifically for students who begin school with less language experience if we can't define the characteristics of these children and collect data on practice designed to help them? (Beyond phonemic awareness measures????.) These are not LD children (for starters anyway). Statistical learning, for example, beckons us toward potential approaches for these children. But if we can't say who we are trying to help, how can we know what works best for which types of students? (We sure do like to categorize LD students in the effort to best serve them.) I worry about how this problem contributes to the research to practice gap and achievement gaps. Thank you.

Jade Weathers Sep 09, 2018 06:04 PM


In regards to Rachel's comment, respectfully, I think you are missing the point. The term "Poverty kids" has a different connotation than the term "kids in poverty". "Poverty kids" sounds like a gang and a rather permanent label. Although poverty is not always permanent but can be situational. Although it does not upset you, I would think that you would consider the audience to whom you address a bit more carefully. While I do understand and lament at times the hypersensitivity of policing language, I don't think that was Rachel's intention. We do need organizational terms in order to work accordingly but we must also understand that we are creating labels for people that did not ask for them nor see themselves that way.

Richard Long Sep 09, 2018 06:06 PM

Science has a good way of policing itself. This issue of how to measure a vocabulary gap is a good example. What was the state of observational research 25 years ago has improved significantly. What also has to evolve is our thinking on the implications of a vocabulary gap and how is impacted by various behaviors. To me the questions are now about: "how are we working with parents to change their verbal interactions with their children?" "How are we changing early childhood learning and care programs to enhance verbal interactions?" Whether the gap is 30 million or over 4 million; the key to those two reports is that there is a gap; and that the gap is sensitive to the environment.

Tim Shanahan Sep 09, 2018 09:54 PM

I get it. But it’s a way of deflecting. Whenever anything sensitive is discussed, it can easily disregarded in favor of faux sensitivities. Oh, that isn’t exactly the right term so let’s ignore the point. I don’t necessarily disagree as to Rachel’s positive purpose (though I honestly don’t know her purpose), but the outcome is the same as it would be if her purpose were negative. Instead of focusing on the needs of children living in poverty, we’re off on stuff that ultimately doesn’t matter.


Rachel Klingelhofer Sep 09, 2018 10:21 PM

Hi again.

I just need to clarify that the purpose for my comment is that in the heated discussions I’ve witnessed regarding these two studies, I’ve heard the more recent study touted as “the truth” by people who resent the way people living in poverty are talked about as families and parents, and frame the earlier study as racist/classist. That has been the most salient theme in all the discussions I’ve heard about this challenge to the Hart & Risley study, both in person and in the media. (Perhaps that has not been the experience of others, but it has been very loaded with all the “isms” in my sphere of work.)

Therefore, I think being careful with our language when discussing it can help because the people I’ve met who want to disregard Hart & Risley’s larger point about the importance of early language exposure and kids’ different amounts of exposure will miss the point completely if they feel those discussing it are doing what they critique Hart & Risley for doing. I wasn’t saying it was horrible nor trying to be picky; I simply think it’s problematic for this specific topic in particular.

So my purpose was not to police, but to point out that language can turn people away from the important conversation if they feel labeled or objectified. When I think of the kids I work with, many of whom live in poverty, I feel uncomfortable with them being labeled that way, but can overlook it enough to learn from the conversation. I know others who would feel more than uncomfortable, and thus leave (literally or internally) the conversation.

Tim Shanahan Sep 10, 2018 02:53 AM

Rachel— I agree that there are folks who reject the entire body of research on the language challenges faced by wonderful children who’s mothers and/or fathers may be living at this time below the federal poverty line in terms of their current incomes through no fault of their own (I guess that is better than poverty kids) as racism.... I appreciate your concern and you certainly might be right but I really disagree with caving in to those claims since they tend to warn policy makers from addressing the well identified problem.



Harriett Janetos Sep 10, 2018 11:46 AM

In her TED Talk and in her articles Anne Fernald is very mindful of this dilemma. At one point in the video, when she introduces two children she is about two discuss, she quietly interjects, "both loved". I, too, grew up in poverty with the triple threat: low income, single parent, immigrant household. I'm grateful that my reality wasn't ignored by my wonderful elementary school teachers. And I often see in the eyes of my students' parents my own mother looking back at me, which makes me that much more committed to address their needs.

Kristin Ward Sep 13, 2018 12:49 AM

Thank you for this article as I have been speaking to colleagues about this research as well as the importance of early childhood education for all. As a teacher with a background in inner-city immigrant youth, I have seen the marked difference EL students from families (both currently living in poverty) who are living in literate verse non-literate homes; which supports the research about complexity and types of unique words that students hear.

That being said, I have grown increasingly concerned about how technology has stopped FAMILIES from talking. In restaurants, everyone (including young children) are glues to tablets and phones. At the market, toddlers are watching videos so, they will be quiet. Few people are walking through produce talking about the colors of fruit and the shape of vegetables. It will be curious to see the impact of technology on vocabulary development in children regardless of SES, not to mention social skills and social interactions.

Tim Shanahan Sep 13, 2018 02:26 PM

Good point. I’ve noticed that in my own home life and I try to be particularly vigilant about putting away the my screens when I’m with my grandkids.



Brian Spivey Sep 19, 2018 12:15 AM

The TED talk is very powerful. I recommend everyone who reads this post watch or at least listen to it (or you can download it and read it if you like).

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Is There Really a 30 Million-Word Gap?


One of the world’s premier literacy educators.

He studies reading and writing across all ages and abilities. Feel free to contact him.