Table S7.
Sibship size | Between-family | Within-family | |||||||||||
n | Observed mean scores by birth-order position | Effect of sibship size | Effect of birth order | n | Estimated mean scores by birth-order position | Effect of birth order | |||||||
Firstborn | Later-borns | F | P | F | P | Firstborn | Later-borns | F | P | ||||
Extraversion | 2 | 8,964 | 49.92 | 50.23 | 2.30 | 0.129 | 1,354 | 49.81 | 49.93 | 0.05 | 0.821 | ||
3 | 5,497 | 50.15 | 50.42 | 0.93 | 0.334 | 861 | 49.34 | 48.97 | 0.28 | 0.595 | |||
4 | 2,569 | 50.87 | 49.72 | 7.24 | 0.007 | 375 | 49.92 | 50.13 | 0.04 | 0.835 | |||
17,030 | 1.12 | 0.327 | 0.60 | 0.437 | 2,590 | 0.01 | 0.939 | ||||||
Emotional stability | 2 | 8,964 | 50.34 | 49.95 | 3.57 | 0.059 | 1,354 | 50.71 | 49.93 | 2.41 | 0.121 | ||
3 | 5,497 | 50.22 | 50.22 | 0.00 | 0.950 | 861 | 50.05 | 49.69 | 0.29 | 0.589 | |||
4 | 2,569 | 49.60 | 49.95 | 0.68 | 0.410 | 375 | 48.73 | 49.73 | 1.08 | 0.300 | |||
17,030 | 1.13 | 0.323 | 1.13 | 0.288 | 2,590 | 1.14 | 0.286 | ||||||
Agreeableness | 2 | 8,964 | 49.97 | 49.93 | 0.04 | 0.852 | 1,354 | 49.51 | 50.19 | 2.07 | 0.151 | ||
3 | 5,497 | 50.05 | 50.34 | 1.10 | 0.294 | 861 | 50.57 | 50.32 | 0.17 | 0.685 | |||
4 | 2,569 | 50.10 | 50.28 | 0.17 | 0.683 | 375 | 48.22 | 50.08 | 3.01 | 0.084 | |||
17,030 | 1.45 | 0.234 | 0.41 | 0.521 | 2,590 | 2.22 | 0.136 | ||||||
Conscientious-ness | 2 | 8,964 | 49.99 | 50.02 | 0.00 | 0.944 | 1,354 | 50.00 | 49.84 | 0.10 | 0.753 | ||
3 | 5,497 | 50.04 | 50.25 | 0.48 | 0.488 | 861 | 49.85 | 49.30 | 0.75 | 0.387 | |||
4 | 2,569 | 50.28 | 49.78 | 1.20 | 0.274 | 375 | 50.77 | 51.36 | 0.34 | 0.562 | |||
17,030 | 0.71 | 0.491 | 0.01 | 0.935 | 2,590 | 0.25 | 0.615 | ||||||
Openness to experience | 2 | 8,964 | 50.48 | 50.12 | 3.17 | 0.075 | 1,354 | 50.31 | 50.19 | 0.05 | 0.817 | ||
3 | 5,497 | 50.79 | 50.35 | 2.47 | 0.116 | 861 | 49.97 | 48.90 | 2.98 | 0.085 | |||
4 | 2,569 | 49.85 | 49.53 | 0.52 | 0.469 | 375 | 49.42 | 50.48 | 1.15 | 0.284 | |||
17,030 | 6.78 | 0.001 | 6.06 | 0.014 | 2,590 | 0.55 | 0.460 | ||||||
Imagination | 2 | 7,232 | 50.14 | 50.12 | 0.01 | 0.922 | 622 | 49.87 | 49.95 | 0.01 | 0.908 | ||
3 | 4,471 | 50.71 | 50.25 | 2.35 | 0.126 | 278 | 49.28 | 50.22 | 0.86 | 0.354 | |||
4 | 2,149 | 49.94 | 49.72 | 0.21 | 0.650 | 100 | 49.36 | 51.69 | 1.42 | 0.238 | |||
13,852 | 3.09 | 0.045 | 1.19 | 0.275 | 1,000 | 0.87 | 0.353 | ||||||
Intellect | 2 | 7,232 | 51.01 | 50.01 | 19.43 | 0.000 | 622 | 51.45 | 49.54 | 7.31 | 0.007 | ||
3 | 4,471 | 50.94 | 50.05 | 8.60 | 0.003 | 278 | 50.53 | 48.80 | 2.65 | 0.105 | |||
4 | 2,149 | 50.02 | 49.30 | 2.25 | 0.134 | 100 | 52.35 | 51.03 | 0.55 | 0.460 | |||
13,852 | 6.42 | 0.002 | 29.68 | <0.001 | 1,000 | 10.55 | 0.001 | ||||||
Intelligence (IQ) | 2 | 6,492 | 102.58 | 101.45 | 13.45 | <0.001 | 896 | 100.94 | 98.38 | 17.84 | <0.001 | ||
3 | 4,424 | 101.19 | 99.47 | 17.71 | <0.001 | 658 | 99.74 | 97.75 | 6.15 | 0.014 | |||
4 | 2,371 | 98.39 | 97.51 | 2.08 | 0.150 | 252 | 97.60 | 94.03 | 6.84 | 0.010 | |||
13,287 | 77.72 | <0.001 | 31.04 | <0.001 | 1,806 | 29.18 | <0.001 |