Concordance for Twins
concordanceCor(
object,
cif1,
cif2 = NULL,
messages = TRUE,
model = NULL,
coefs = NULL,
...
)Output from the cor.cif, rr.cif or or.cif function
Marginal cumulative incidence
Marginal cumulative incidence of other cause (cause2) if it is different from cause1
To print messages
Specfifies wich model that is considered if object not given.
Specfifies dependence parameters if object is not given.
Extra arguments, not used.
The concordance is the probability that both twins have experienced the event of interest and is defined as $$ cor(t) = P(T_1 \leq t, \epsilon_1 =1 , T_2 \leq t, \epsilon_2=1) $$
Similarly, the casewise concordance is $$ casewise(t) = \frac{cor(t)}{P(T_1 \leq t, \epsilon_1=1) } $$ that is the probability that twin "2" has the event given that twins "1" has.
Estimating twin concordance for bivariate competing risks twin data Thomas H. Scheike, Klaus K. Holst and Jacob B. Hjelmborg, Statistics in Medicine 2014, 1193-1204
Estimating Twin Pair Concordance for Age of Onset. Thomas H. Scheike, Jacob V B Hjelmborg, Klaus K. Holst, 2015 in Behavior genetics DOI:10.1007/s10519-015-9729-3