I.Q., Second Retests, 21 Pairs
| N[16] | Test Group (A) | Control Group (B) | |||||
| Test 1 | Test 3 | Gain | Test 1 | Test 3 | Gain | A-B | |
| 27 | 110 | 112 | 2 | 72 | 98 | 26 | -24 |
| 15 | 97 | 97 | 78 | 98 | 20 | -20 | |
| 3 | 94 | 91 | -3 | 82 | 96 | 14 | -17 |
| 7 | 91 | 93 | 2 | 95 | 112 | 17 | -15 |
| 20 | 106 | 116 | 10 | 118 | 140 | 22 | -12 |
| 23 | 85 | 80 | -5 | 81 | 88 | 7 | -12 |
| 8 | 91 | 92 | 1 | 98 | 111 | 13 | -12 |
| 12 | 98 | 86 | -12 | 98 | 91 | -7 | -5 |
| 21 | 64 | 66 | 2 | 86 | 93 | 7 | -5 |
| 4 | 96 | 111 | 15 | 83 | 102 | 19 | -4 |
| 13 | 70 | 61 | -9 | 66 | 60 | -6 | -3 |
| 18 | 98 | 101 | 3 | 90 | 92 | 2 | 1 |
| 16 | 65 | 74 | 9 | 74 | 81 | 7 | 2 |
| 10 | 110 | 116 | 6 | 104 | 107 | 3 | 3 |
| 28 | 81 | 83 | 2 | 95 | 94 | -1 | 3 |
| 11 | 103 | 102 | -1 | 101 | 95 | -6 | 5 |
| 1 | 82 | 93 | 11 | 80 | 85 | 5 | 6 |
| 14 | 96 | 102 | 6 | 140 | 138 | -2 | 8 |
| 19 | 96 | 97 | 1 | 98 | 90 | -8 | 9 |
| 2 | 107 | 113 | 6 | 91 | 86 | -5 | 11 |
| 9 | 83 | 102 | 19 | 87 | 91 | 4 | 15 |
| Av. | 91·5 | 94·6 | 3·0 | 91·2 | 97·5 | 6·2 | -3·1 |
| M | 2 | 5 | -3 | ||||
| 75%ile | 6 | 13·75 | 4·5 | ||||
| 25%ile | -·75 | -4·25 | -12 | ||||
| Q | 3·37 | 9·00 | 8·25 | ||||
| P. E. (distribution) | 2·09 | 8·24 | 8·86 | ||||
| P. E. (average) | ±·45 | ±1·79 | ±1·84 | ||||
| Av.=-1·71 P. E. | |||||||
| M.=-1·63 P. E. | |||||||
| Lost in 2nd period | Gained in 2nd period | No change | Gained equally with gain in 1st period | |
| Test group | 9 | 11 | 1 | 9 |
| Control group | 10 | 11 | 8 |
The average gain of the test group was 3·09 points after 12 months, compared with 2·25 after six. The control group, however, made an average gain of 6·24 after 12 months, the gain after six months being 3·29. These numbers are insignificant as gains, but they at least show no improvement in the test group which the control group does not reveal as well. On the basis of the results, we may say that there has been no improvement in I.Q. as a result of operation, either after six months or after twelve.
There remains to be considered only the result of the Healy Picture Completion Test. We have scores in this test for 18 pairs of cases. When these scores are compared with those in the former tests, the results stand as follows:
| Average of gains of test group in excess of control | -5·85 | -3·36 |
| Median of gains of test group in excess of control | -7·75 | 1·00 |
| P. E. of difference | ±3·05 | ±3·38 |
| Average in terms of P. E. | -1·92 | -·87 |
| Median in terms of P. E. | -2·54 | ·26 |
The figures given above show no gain in the Healy test as a result of operation. Both after six months, and after twelve, we find that the test group has gained no more than the control group. As before there are individual cases showing considerable gain in the second period, but these are matched by control cases which reveal equal or even greater gains. In the test group, 5 cases lost in the second period in comparison with the first, 18 gained, and 7 gained as much in the second period as in the first. The control group lost in the second period in 5 cases, gained in 18, and gained as much as in the first period in 7 cases. The two groups, then, are practically equal, both showing a gain in the second period, but this gain cannot be due to the operations, since the control group did not undergo operation.
TABLE XXII
Healy A, Second Retests, 18 Pairs
| N[16] | Test Group (A) | Control Group (B) | ||||||
| Test 1 | Test 3 | Gain | Test 1 | Test 3 | Gain | A-B | ||
| 12 | 20 | 1 | -19 | -10 | 41.5 | 51·5 | -70·5 | |
| 23 | 49·5 | 62·5 | 13 | 4 | 64 | 60 | -47 | |
| 15 | 7 | 19 | 12 | 1 | 54·5 | 53·5 | -41·5 | |
| 1 | -22 | 11 | 36 | -50 | 11 | 61 | -25 | |
| 2 | 28·5 | 24·5 | -4 | 3 | 19·5 | 16·5 | -20·5 | |
| 3 | 21·5 | 15·5 | -6 | 17 | 25·5 | 8·5 | -14·5 | |
| 19 | 57·5 | 60·5 | 3 | -22 | -15 | 7 | -4 | |
| 13 | 43 | 62·5 | 19·5 | -1·5 | 21·5 | 23 | -3·5 | |
| 21 | 20 | 38 | 18 | 70·5 | 88 | 17·5 | ·5 | |
| 10 | -12 | 11 | 23 | 27 | 48·5 | 21·5 | 1·5 | |
| 14 | 12·5 | 77 | 64·5 | -5 | 48·5 | 53·5 | 11 | |
| 27 | -25 | 25·5 | 50·5 | 2 | 39·5 | 37·5 | 13 | |
| 11 | -8 | 15·5 | 23·5 | -29 | -20 | 9 | 14·5 | |
| 16 | 49 | 79 | 30 | 30 | 45·5 | 15·5 | 14·5 | |
| 7 | -6 | 16 | 22 | 45 | 11 | 6·5 | 15·5 | |
| 28 | 29·5 | 77·5 | 48 | 64·5 | 83·5 | 19 | 29 | |
| 18 | -13·5 | 13·5 | 27 | -32 | -35 | -3 | 30 | |
| 20 | 0 | 55 | 55 | 30 | 48·5 | 18·5 | 36·5 | |
| Av. | 13·81 | 36·92 | 23·11 | 5·77 | 32·25 | 26·47 | -3·36 | |
| M | 22·5 | 18·75 | 1 | |||||
| 75%ile | 33 | 44 | 14·5 | |||||
| 25%ile | 7·5 | 8·75 | -22·25 | |||||
| Q | 12·75 | 17·62 | 18·37 | |||||
| P. E. (distribution) | 11·5 | 17·72 | 17·86 | |||||
| P. E. (average) | ±2·7 | ±4·22 | ±3·88 | |||||
| Av.=-·87 P. E. | ||||||||
| M.=+·26 P. E. | ||||||||