Truncated time-dependent concordance index

C^td(t) = P(marker_i > marker_j | T_i < T_j, T_i <= t, delta_i = 1), marker ties counting one half – Antolini, Boracchi and Biganzoli (2005) with a scalar marker, equal to Harrell's C truncated at t.

Usage

Survtdc(time, event, marker, t)

Arguments

time: Observed times.
event: Event indicators (1 = event, 0 = censored).
marker: Scalar risk marker, higher = riskier.
t: Truncation horizon.

Value

List with estimate, concordant, tied, comparable, t, method.

References

Antolini, L., Boracchi, P. and Biganzoli, E. (2005), Statistics in Medicine 24(24), 3927-3944.

Examples

Survtdc(time = c(2.5, 1.0, 3.5, 4.0, 2.0, 5.5, 3.0, 6.5), event = c(0, 1, 0, 1, 1, 0, 1, 0),
  marker = c(1, 2, 3, 4, 5, 6, 7, 8), t = c(1, 2, 3, 4, 5, 6, 7, 8))
#> $estimate
#> [1] 0.1428571
#> 
#> $concordant
#> [1] 1
#> 
#> $tied
#> [1] 0
#> 
#> $comparable
#> [1] 7
#> 
#> $t
#> [1] 1
#> 
#> $method
#> [1] "Antolini-Boracchi-Biganzoli (2005) truncated time-dependent concordance"
#>