The base nLTT statistic can be used as a semi stand-alone statistic for phylogenetic trees. However, please note that although this provides a nice way of checking the power of the nLTT statistic without directly comparing two trees, the nLTT_base statistic is not a substitute for directly comparing two phylogenetic trees. E.g. one would perhaps naively assume that \(nLTT(A, B) = |nLTT(A, base) - nLTT(B, base)\). Indeed, in some cases this may hold true (when, for instance, all normalized lineages of A are less than all normalized lineages of B), but once the nLTT curve of A intersects the nLTT curve of B, this no longer applies.
Examples
simulated_tree <- ape::rphylo(n = 10, birth = 1, death = 0)
nLTT_base(simulated_tree)
#> [1] 0.5631948