It will be noticed that the fastest child read more than twice as fast as the slowest. Similar differences appear in the other grades, as shown in the table below; for example, the slowest children in 6 A read from 151 to 175 words per minute, while the fastest read from 376 to 400 words. A page of this book contains about 400 words; hence if it contained easy story material the fastest reader in the sixth grade would read a page in about one minute, while the slowest would take more than two minutes.

In larger classes, fastest reading rate equals three or four times the slowest. The above differences were found in the Elementary School of The University of Chicago, where the children are very carefully graded into small classes and individual promotions and demotions are carefully made. In public-school classes where larger groups

prevail, and individual adjustments are less frequent, slightly greater differences often occur, as shown by the following results from the same test:

COURTIS SILENT READING TEST

(Results from large classes, not closely graded1
Read each row horizontally)

Fastest

Even greater differences in arithmetic scores. equals eight times slowest. When we turn from differences in reading rate to differences in speed in working arithmetic problems an even greater contrast appears between the slow and the fast pupils. For example, Courtis reports from tests of a New York City eighth grade containing 48 children the following results in an arithmetic test. (23: 333)

Quality of arithmetical thinking less restricted by physiological limits. From this table it appears that the slowest child made a score of 2, while the brightest made a score of 17, or eight times as large as the slowest. This

1 These results were kindly furnished by Mr. S. A. Courtis from his private files.

difference is greater than that found in the case of readingrates where the fastest child read only two to four times as fast as the slowest in the same class. In the case of rapid silent reading, without skipping, scarcely any adult reads at a greater rate than 700 words per minute. There seems to be a physiological limit which cannot be passed a limit which is probably set by the rapidity with which the eyes can move across the page and see the print during the pauses which they make. In the case of arithmetic problems, however, one's speed is much less restricted by such physiological matters; that is, one can work problems almost as fast as one can think. This fact probably explains the greater disparity between the slow and the fast in arithmetic, the difference between the worst and the best being largely a difference in the speed of thinking or the quality of the thinking.

Objective, precise measures of differences in quality of achievement are difficult to devise. It is very much more difficult to compare and measure differences in the quality of mental products than differences in the quantity. For this reason we began with rates of reading, — words per minute, — where the measurements are in objective units (number of words and minutes) which are tangible, reliable, and easy to compare. In the case of arithmetic, the task of measuring precisely differences in achievement is somewhat more difficult than in rates of reading, owing to the necessity of devising lists of problems in which the relative difficulty of the problems is known. However, experts in educational measurement have devised such lists, and the results from the Courtis test described on page 292, above, furnish one example of their use. When we try to measure differences in certain other abilities, such as the ability to write compositions, the difficulties of precise measurement are greatly increased. However, even here educational experts have succeeded in arranging sample compositions according to

their quality so as to give us a scale for measuring differences in abilities in composition. The first scale for this purpose was made about 1912 by Professors Thorndike and Hillegas after many months of study and experimentation. The sample composition which they used in their scale to represent approximately zero ability began as follows:

Dear Sir: I write to say that it aint a square deal Schools is I say they is I went to a school. red and gree green and brown aint.

Qualities of compositions compared precisely by composition scales. - In order to devise a measurement scale for comparing the composition abilities of sixth-grade children, Breed and Frostic (25) secured a large number of compositions written by such children under exactly similar conditions upon the same theme. The pupils were asked to finish in writing a story which told about a picnic party of some children and their teacher. The story described their starting in a motor boat, the engine of which stopped after they had proceeded some distance. The pupils who wrote the compositions were told to imagine what followed and to complete the story. One of the poorest papers handed in read as follows:

.2

The hanjict shop for there there was so many in it. After

a little they it going. And

they to pleace were the the picine

was. They all get out of the
hounce and but there thing
down

on the table and rain out to
play. After they were platy
the had there lunce. And
They had a very nice time.

A somewhat better paper read in part as follows:

2.7

When the enginer stop, one

of the boy took his shoes and

off

stcocking and got out into the
river and bushe the bout a little

so as to stare the enginer

a going, when that had

stared the bowt went aright.

And they went rideing

around the river where

having a nice time went

one of the girl saw a water—

lillies and they try to pick when she

fell in the river but she got

aright, her cloth were wet

some but they soon try, and
she got her water lillies.

When they were throu

ght rideing they got out and

A composition of average merit began thus:

4.7

Jack the one who was runing

the launch said, "lets take these pales
and push the launch to shore. Yes! Yes!
let do said all; we took the poles
and tu) pushed it to shore. Jack
got out and looked around. He saw
a house over yonder, he went over
to see if they had any gasoline,
when. he got there and ask they
had none. When he came back