LikeLTD software

likeLTD (likelihoods for low-template DNA profiles)

likeLTD is an R package for computing likelihoods for DNA profile evidence, including complex mixtures and when profiles are subject to dropout.


likePHguideV6-2.pdf (Version 6.2, March 2017)

This gives information on installing and running, an illustrative analysis, a description of the model, validation study, version history and acknowledgments. Version 6.2 includes changes to the allele and output reports, changing the format that various information is presented in, and including warnings for some situations that the user may need to be aware of. A bug that was preventing output report generation in some circumstances was fixed. Peaks that are below the detection threshold are now removed from the CSP automatically. The computation of which unknown contributors may be explained as dropin has been altered slighly, computing the contribution of Q on only alleles that are unshared with any K. The underlying peak height likelihood model has not been altered.

The above Guide only covers the new peak height model, for the discrete model (which remains in Versions 6, 6.1 and 6.2, essentially unchanged from Version 5.5), see the previous guide:

likeLTDguide.pdf (Ver 5.5, March 2015)

For an example witness statement illustrating how likeLTD results can be presented in court, see:

Sample witness statement using results from  likeLTD

likeLTD is a team effort, early versions were coded by David Balding, Adrian Timpson and the UCL Research Software Development Team, in particular Mayeul d’Avezac, contributed much to versions 4 and 5, while the peak height model in Ver 6 has been developed and coded by Christopher Steele.

A publication describing Ver 6.0 is available here:

For Versions 5 through 5.5 the most relevant publication is:

which gives a description of the statistical model, and examples of analyses of real cases and results from simulations.  Other relevant publications:

Please send comments and report any bugs to Chris Steele at