Frailty Model                 Independent Model
Penetrance     k      Bias%      SE      RMSE      Bias%      SE      RMSE
High 2 0.47 0.099 0.138 -15.10 0.085 0.181
  4 0.50 0.099 0.135 -8.49 0.087 0.143
  8 0.46 0.097 0.131 -4.43 0.088 0.125
Low 2 -0.19 0.095 0.130 -5.22 0.089 0.130
  4 -0.52 0.097 0.132 -3.13 0.094 0.129
  8 -0.12 0.098 0.134 -1.57 0.097 0.132
Bias% = Bias×100
Table 1: (Shared frailties) Estimating the log relative risk (RR) of the major gene effect: Bias, robust standard error (SE) and root mean square error (RMSE), comparison of frailty and independent modeling approaches.