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Table 1 Test-retest reliability results

From: Testing assumptions for endophenotype studies in ADHD: Reliability and validity of tasks in a general population sample

Measure inter-class r partial ra intra-class r time 1 time 2 t-value df p
     mean SD mean SD    
Fast Task (n = 41)
baseline (all trials)
   mean RT .85 .75 .77 730.31 177.76 659.24 156.71 4.89 40 <.001
   SD of RTs .60 .53 .58 193.77 103.55 171.86 118.49 1.40 40 .17
baseline (30 trials)
   mean RT .76 .53 .68 670.64 155.09 603.32 138.74 3.75 40 .001
   SD of RTs .47 .37 .43 155.78 68.90 141.59 97.80 0.93 40 .36
fast-incentive
   mean RT .89 .79 .82 537.69 121.55 499.78 100.97 4.29 40 <.001
   SD of RTs .76 .65 .70 122.80 50.63 105.34 47.43 3.25 40 .002
Go/No-Go (n = 44–47)
slow condition
   mean RT .76 .63 .74 512.00 105.13 532.07 112.06 -1.77 44 .08
   SD of RTs .58 .53 .58 177.51 115.86 172.33 123.30 .315 44 .75
   commission errors .56 .56 .53 45.19 23.18 36.59 22.46 2.69 44 .01
fast condition
   mean RT .88 .85 .87 387.20 74.69 385.24 64.58 0.37 44 .71
   SD of RTs .83 .82 .83 147.42 69.48 147.02 65.80 0.07 44 .95
   commission errors .70 .67 .64 42.54 16.99 38.62 17.89 1.93 44 .06
incentive condition
   mean RT .70 .63 .69 508.64 91.44 526.48 79.26 -1.77 43 .08
   SD of RTs .26b .09b .26 119.52 47.43 122.91 40.47 -0.42 43 .68
   commission errors .54 .47 .52 25.95 16.30 21.82 16.97 1.72 43 .09
  1. a controlling for age b inter-class r increases to .61 and partial r to .44, if exclude six potential outliers (see text for further information)