lrSibDebug {relSim}

Likelihood Ratio / Kinship Index for full-siblings

Description

Calculates Likelihood Ratio comparing the probability of two profiles if they are indeed full-sibs compared to unrelated. This is sometimes called the kinship index (KI) for full-sibs. This function is identical to lrSib except that the calculation is performed in R, and provides full calculation detail at each locus. It exists primarily to check that the correct formula and logic is being applied in the LR calculation so that the result can be manually verified.

Usage

lrSibDebug(sib1, sib2, Freqs)

Arguments

sib1

A matrix consisting of 2 columns and nLoci rows. Each entry in the matrix is the (coded) allele held by the individual. This represents the alleged sibling. The relationship is reflexive so it does not matter which profile is labelled sib1 and sib2.

sib2

See sib1

Freqs

A list containing two lists labelled loci and freqs. The second list is a list of vectors containing the allele frequencies of each allele at each locus in the multiplex.

Value

A list containing three elements Lines, lr, and Cases. Lines is a list of strings containing the calculation at each locus so that the result can be written to file for example. Cases is a numeric code listing which logical case (1-11) the locus falls into for the profiles in question. lr is the KI for full-sibs for the two profiles.

Author(s)

James M. Curran

References

Buckleton, J, Triggs, C.M., and Walsh, S.J. (2005)Forensic DNA Evidence Interpretation, CRC Press., Boca Raton, FL. p.411

See Also

lrSib, lrPC, IBS

Examples

data(fbiCaucs)
P1 = randomProfile(fbiCaucs)
S1 = randomSib(P1, fbiCaucs)
P2 = randomProfile(fbiCaucs)
cat(paste(lrSibDebug(P1, S1, fbiCaucs)$Lines))
cat(paste(lrSibDebug(P1, P2, fbiCaucs)$Lines))