Here are the phrases, from Edward Dolch, the creater of the Dolch sight words, in his 1948 book, “Problems in Reading.” The first is on p. 56:
There is the famous 'fourth-grade hump,' the sudden difficulty of reading matter that strikes the children without warning. The difficulty keeps on climbing through grades V and VI.
This mention on page 251 also has a very interesting table:
Every word not on the list of 1,000 [most frequent words] was underlined and counted every time it appeared. Therefore a percentage of hard words means a percentage of the running words, that is, the total words read. We are aware that if a word appears a second time it is not now a hard word if it were learned the first time, but there was no way of allowing for this factor.....
The percentages of hard words for the books of each grade were averaged, and then the figures were rounded to the nearest whole number. The result shows the following:
TABLE V
Word Difficulty, According to Appearance on First 1,000 Words for
Children’s Reading as Found in Ten Series Of Readers
Grade
I II III IV V VI
Hard Words (Not on List)
4% 6% 8% 12% 14% 16%
These figures show the well-known “fourth grade hump,” a difference between the third grade books and fourth grade books that is twice the difference between the other grades.
There were several interesting links to later use of the phrase “4th grade slump,” I’ll link to two of them:
- The Trouble With Boys by Peg Tyre, p. 142-143
(The whole thing is interesting, here’s an excerpt:)
Around fourth and fifth grade, another factor comes into play as well. Good readers take a leap forward as they move from learning to read to reading to learn. The curriculum demands it. It’s no longer enough to be able to “sound out” words. Children have to comprehend sentences and paragraphs from history and science books and make inferences from those texts. Kids who don’t make that jump fall into what experts have dubbed the “fourth-grade slump.” They are stuck trying to figure out how to decode the word everglades, for instance, while other kids are learning about the kinds of animals that live in those Florida swamps. It’s an important cognitive leap.
By every measure, the fourth-grade slump hits boys harder than it hits girls.
2. The Reading Crisis: Why Poor Children Fall Behind by Chall, Jacobs, and Baldwin, p. 143
As predicted by the theoretical model of reading used for our study (see Chapter 1), the students’ scores started to slump at about grade 4. For the below-average readers, the slump began early (in grade 4) and was intense. By grades 6 and 7, they were reading almost two years below grade level on all the reading tests. For the above-average readers, the slump began later (around grade 6) and was less intense. Many of the above-average readers were still reading on grade level or above in the sixth and seventh grades on some of the reading tests.The slump started earlier on some tests than on others.
The first to slip was vocabulary.
If you teach properly, with a good phonics method and less than a dozen sight words, there are few "hard words;" disadvantaged elementary children (including several 1st graders) taught with Webster's Speller were able to sound out what Dolch called "hard words," but Webster called "easy words of X syllables."
Here are some "easy words of 3 syllables, accented on the first and third"
O-VER-TAKE, IN-COR-RECT, IN-TER-MIX
and "easy words of 4 syllables, full accent on the first, and the half accent on the third"
MIS-CEL-LA-NY, OB-DU-RA-CY, PUR-GA-TO-RY