Table 2.
Exploring statistical power to detect genetic influence on the association between parental criticism and adolescent internalising symptoms (r=.29)a
| Specified/estimated parameters | %rPh attributable to A1’ | Power to detect A1’ (α=.05) | ||||||
|---|---|---|---|---|---|---|---|---|
| E1 | A1 | E2 | A2 | A1’ | p | |||
| Data simulated to match study results | .74/.74 | .26/.26 | .39/.42 | .48/.45 | .05/.05 | .24/.24 | 19 | .58 |
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| ||||||||
| Data simulated to manipulate study results | .74/.74 | .26/.26 | .39/.41 | .00/.00 | .53/.54 | .11/.11 | 63 | 1.0 |
| .74/.74 | .26/.26 | .39/.41 | .10/.09 | .43/.44 | .13/.13 | 56 | 1.0 | |
| .74/.74 | .26/.26 | .39/.41 | .20/.19 | .33/.34 | .15/.15 | 50 | 1.0 | |
| .74/.74 | .26/.26 | .39/.41 | .30/.29 | .23/.23 | .17/.17 | 42 | 1.0 | |
| .74/.74 | .26/.26 | .39/.41 | .40/.38 | .13/.13 | .21/.21 | 31 | .95 | |
| .74/.74 | .26/.26 | .39/.41 | .44/.41 | .09/.09 | .22/.22 | 26 | .83 | |
| .74/.74 | .26/.26 | .39/.41 | .45/.43 | .08/.08 | .22/.22 | 25 | .79 | |
We simulate data for 876 adult twin pairs with one child per twin and 1030 adolescent twin pairs with one parent per pair. Study results informed parameter specifications: heritability of parental criticism was .26 (A1); heritability of adolescent internalising was .53 (A1’+A2). Each row represents a new model. A1’ specification was varied across models to manipulate the percentage of rPh (phenotypic correlation) attributable to genetic influence. Corresponding changes were made to A2 and p specifications, to preserve heritability estimates and rPh in each model. Variance components are shown for latent factors (E1/A1/E2/A2/A1’), whereas p is a standardised path coefficient. Bolded text shows the model where 80% power to significantly detect A1’ was reached.