The following materials and equipment are required:
(1) A set of printed cards consisting of four pictures used in 3-, 7-, and 12-year tests; lines for comparison used in 4-year test; geometrical forms for discrimination, in duplicate, used in 4-year test; printed colors used in 5-year test; printed faces for aesthetic comparison used in 5-year test; pictures with missing parts used in 6-year test; designs for drawing from memory used in 10-year test; code used in "average adult" test; and scoring cards for square, diamond, ball and field, dictation, and designs used in 4-, 7-, 8-, and 10-year tests.2
(2) Record booklets, which are necessary not only for the proper and convenient recording of the results of tests, but also because they contain some of the testing equipment: sentences and digit series for repetition used in 3, 4, 6, 7, 9, and all the higher age tests; square used in 4-year test; diamond used in 7-year test; ball field used in 8- and 12-year tests; the correct wording for comprehension tests used at various ages; printed form for 10-year test for reading and report; and all problems, fables, vocabulary, etc., used in tests at various ages.1
1 L. M. Terman. The Measurement of Intelligence. Boston, 1916. - We acknowledge gratefully our indebtedness to Professor Terman and the publishers of his book, Houghton, Mifflin Company, for permission to abstract and reprint instructions for testing, scoring, etc.
2 These printed materials are to be had from Houghton, Mifflin Company, Boston, New York, or Chicago. Price 60 cents, postpaid.
(3) Weights used in 5- and 9-year tests and the Healy-Fernald construction puzzle used in 10-year alternative test.2
(4) The following articles: coins - $1, 50 cents, quarter, dime, nickel, thirteen pennies; large-sized doorkey, not of the Yale type; pocket knife; watch with second hand; scissors; three one-cent and three two-cent stamps mounted in a single row on a blank card of suitable size, in the order given; two shoe strings; ordinary lead pencil, pen and ink, some cards 2 by 3 inches, pad of paper, and a supply of paper sheets, thin but firm, 8 1/2 by 11 inches; a small rectangular pasteboard box.
The tests should be conducted in a quiet room, located where the noises of the street and other outside distractions cannot enter. Generally speaking, if accurate results are to be secured it is not permissible to have any auditor, besides possibly an assistant to record the responses.
The examiner's first task is to win the confidence of the child and overcome his timidity. In a majority of cases from three to five minutes should be sufficient, but in a few cases somewhat more time is necessary.
Nothing contributes more to a satisfactory rapport than praise of the child's efforts. Under no circumstances should the examiner permit himself to show displeasure at a response, however absurd it may be.
The examiner would avoid testing a child who was exhausted either from work or play, or a child who was noticeably sleepy.
Although we should always encourage the child to believe that he can answer correctly, if he will only try, we must avoid the common practice of dragging out responses by too much urging and coaxing.
1 Record booklets are supplied also by Houghton, Mifflin Company, in packages of 25, at $2 per package, postpaid.
2 These may be purchased of C. H. Stoelting Company, 3037-3047 Carroll Ave., Chicago, 111. The cost of the weights is $2.50 and of the construction puzzle $1.50.
It cannot be too strongly emphasized that unless we follow a standardized procedure the tests lose their significance. The danger is chiefly that of unintentionally and unconsciously introducing variations which will affect the meaning of the test. One who would use the tests for any serious purpose, therefore, must study the procedure for each and every test until he knows it thoroughly. After that a considerable amount of practice is necessary before one learns to avoid slips. During the early stages of practice it is necessary to refer to the printed instructions frequently in order to check up errors before they have become habitual.
In a few cases the instruction may be repeated, if there is reason to think the child's hearing was at fault or if some extraordinary distraction has occurred. But unless otherwise stated in the directions, the repetition of a question is ordinarily to be avoided. Supplementary explanations are hardly ever permissible.
Unless there is reason to suspect mental retardation, it is usually best to begin with the group of tests just below the child's age. However, if there is a failure in the tests of that group, it is necessary to go back and try all the tests of the previous group. In like manner the examination should be carried up the scale until a test group has been found in which all the tests are failed.
If language tests or memory tests are given first, the child is likely to be embarrassed. More suitable to begin with are those which test knowledge or judgment about objective things, such as the pictures, weights, stamps, bow-knots, colors, coins, counting pennies, number of fingers, right and left, time orientation, ball and field, paper-folding, etc."
The tests as arranged in this revision are in the order which it is usually best to follow, but one should not hesitate to depart from the order given when it seems best in a given case to do so.
Each subdivision of a test should be scored separately, in order that the clinical picture may be as complete as possible. This helps in the final evaluation of the results. It makes much difference, for example, whether success in repeating six digits is earned by repeating all three correctly or only one; or whether the child's lack of success with the absurdities is due to failure on two, three, four, or all of them. Time should be recorded whenever called for in the record blanks.
Whenever possible the entire response should be recorded. If the test results are to be used by any other person than the examiner, this is absolutely essential.
When for any reason it is not feasible to record anything more than score marks, success may be indicated by the sign +, failure by - , and half credit by 1/2. An exceptionally good response may be indicated by + +, and an exceptionally poor response by- -. If there is a slight doubt about a success or failure the sign? may be added to the + or - . In general, however, score the response either + or - , avoiding half credit as far as it is possible to do so.
In addition, the examiner will need to take account of the general attitude of the child during the examination. This is provided for in the record blanks under the heading "comments." The comments should describe as fully as possible the conduct and attitude of the child during the examination, with emphasis upon such disturbing factors as fear, timidity, unwillingness to answer, overconfidence, carelessness, lack of attention, etc.
The tests designated as "alternative tests" are not intended for regular use. Inasmuch as they have been standardized and belong in the year group where they are placed, they may be used as substitute tests on certain occasions. Sometimes one of the regular tests is spoiled in giving it, or the requisite material for it may not be at hand. Sometimes there may be reason to suspect that the subject has become acquainted with some of the tests. In such cases it is a good convenience to have a few substitutes available.
It is necessary, however, to warn against a possible misuse of alternative tests. It is not permissible to count success in an alternative test as offsetting failure in a regular test. This would give the subject too much leeway of failure. There are very exceptional cases, however, when it is legitimate to break this rule; namely, when one of the regular tests would be obviously unfair to the subject being tested. In year X, for example, one of the three alternative tests should be substituted for the reading test (X, 4) in case we are testing a subject who has not had the equivalent of at least two years of school work. In year VIII, it would be permissible to substitute the alternative test of naming six coins, instead of the vocabulary test, in the case of a subject who came from a home where English was not spoken.
As there are six tests in each age group from III to X, each test in this part of the scale counts 2 months toward mental age. There are eight tests in group XII, which, because of the omission of the 11-year group, have a combined value of 24 months, or 3 months each. Similarly, each of the six tests in XIV has a value of 4 months (24/6 = 4). The tests of the "average adult" group are given a value of 5 months each, and those of the "superior adult " group a value of 6 months each.
The rule is: (1) Credit the subject with all the tests below the point where the examination begins (remembering that the examination goes back until a year group has been found in which all the tests are passed); and (2) add to this basal credit 2 months for each test passed successfully up to and including year X, 3 months for each test passed in XII, 4 months for each test passed in XIV, 5 months for each success in "average adult," and 6 months for each success in "superior adult."
The mental age alone does not tell us what we want to know about a child's intelligence status. The significance of a given number of years of retardation or acceleration depends upon the age of the child. A 3-year-old child who is retarded one year is ordinarily feeble-minded; a 10-year-old retarded 1 year is only a little below normal. The child who at 3 years of age is retarded 1 year will probably be retarded 2 years at the age of 6, 3 years at the age of 9, and 4 years at the age of 12.
What we want to know, therefore, is the ratio existing between mental age and real age. This is the intelligence quotient, or I Q. To find it we simply divide mental age (expressed in years and months) by real age (also expressed in years and months). The process is easier if we express each age in terms of months alone before dividing.
Native intelligence, in so far as it can be measured by tests now available, appears to improve but little after the age of 15 or 16 years. Accordingly, any person over 16 years of age, however old, is for purposes of calculating I Q considered to be just 16 years old. If a youth of 18 and a man of 60 years both have a mental age of 12 years, the I Q in each case is 12/16, or .75.
The significance of various values of the I Q is set forth elsewhere.1 Here it need only be repeated that 100 I Q means exactly average intelligence; that nearly all who are below 70 or 75 I Q are feeble-minded; and that the child of 125 I Q is about as much above the average as the high grade feeble-minded individual is below the average. For ordinary purposes all who fall between 95 and 105 I Q may be considered as average in intelligence.