Skip to main content
. 2015 Oct 19;112(46):14224–14229. doi: 10.1073/pnas.1506451112

Table S7.

Mean scores and results of between-family analyses (NCDS, NLSY and SOEP) and within-family analyses (NLSY and SOEP) comparing first- and later-borns

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