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IntelligenceKeeping The Child EncouragedUsing A Code Quiet And Seclusion Alternative Test 3: Construction Puzzle A (healy And Fernald) Repeating Four Digits Reversed Alternative Test 1: Repeating Six Digits Reversing Hands Of Clock The Ball-and-field Test (score 2 Inferior Plan) Superior Adult 2: Binet's Paper-cutting Test Giving Definitions In Terms Of Use Naming Four Coins Are Intelligence Tests Superfluous? Distinguishing Right And Left Enumeration Of Objects In Pictures General Value Of The Method Arithmetical Reasoning Arranging Five Weights The Avoidance Of Fatigue Aesthetic Comparison Copying A Diamond |
Reliability Of Repeated TestsWill the same tests give consistent results when used repeatedly with the same subject? In general we may say that they do. Something depends, however, on the age and intelligence of the subject and on the time interval between the examinations. Goddard proves that feeble-minded individuals whose intelligence has reached its full development continue to test at exactly the same mental age by the Binet scale, year after year. In their case, familiarity with the tests does not in the least improve the responses. At each retesting the responses given at previous examinations are repeated with only the most trivial variations. Of 352 feeble-minded children tested at Vineland, three years in succession, 109 gave absolutely no variation, 232 showed a variation of not more than two fifths of a year, while 22 gained as much as one year in the three tests. The latter, presumably, were younger children whose intelligence was still developing. Goddard has also tested 464 public-school children for three successive years. Approximately half of these showed normal progress or more in mental age, while most of the remainder showed somewhat less than normal progress. Bobertag's retesting of 83 normal children after an interval of a year gave results entirely in harmony with those of Goddard. The reapplication of the tests showed absolutely no influence of familiarity, the correlation of the two tests being almost perfect (.95). Those who tested "at age" in the first test had advanced, on the average, exactly one year. Those who tested _plus_ in the first test advanced in the twelve months about a year and a quarter, as we should expect those to do whose mental development is accelerated. Correspondingly, those who tested _minus_ at the first test advanced only about three fourths of a year in mental age during the interval. Our own results with a mixed group of normal, superior, dull and feeble-minded children agree fully with the above findings. In this case the two tests were separated by an interval of two to four years, and the correlation between their results was practically perfect. The average difference between the I Q obtained in the second test and that obtained in the first was only 4 per cent, and the greatest difference found was only 8 per cent. The repetition of the test at shorter intervals will perhaps affect the result somewhat more, but the influence is much less than one might expect. The writer has tested, at intervals of only a few days to a few weeks, 14 backward children of 12 to 18 years, and 8 normal children of 5 to 13 years. The backward children showed an average improvement in the second test of about two months in mental age, the normal children an average improvement of little more than three months. No child varied in the second test more than half a year from the mental age first secured. On the whole, normal children profit more from the experience of a previous test than do the backward and feeble-minded. Berry tested 45 normal children and 50 defectives with the Binet 1908 and 1911 scales at brief intervals. The author does not state which scale was applied first, but the mental ages secured by the two scales were practically the same when allowance was made for the slightly greater difficulty of the 1911 series of tests. We may conclude, therefore, that while it would probably be desirable to have one or more additional scales for alternative use in testing the same children at very brief intervals, the same scale may be used for repeated tests at intervals of a year or more with little danger of serious inaccuracy. Moreover, results like those set forth above are important evidence as to the validity of the test method. Next: Influence Of Social And Educational Advantages Previous: The Influence Of Coaching
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