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strvalidator (version 1.3.0)

modelDropout_gui: model and plot drop-out events

Description

modelDropout_gui model probability of drop-out and plots a graph.

Usage

modelDropout_gui(env = parent.frame(), savegui = NULL, debug = FALSE)

Arguments

env
environment in wich to search for data frames and save result.
savegui
logical indicating if GUI settings should be saved in the environment.
debug
logical indicating printing debug information.

Value

  • TRUE

Details

Models the probability of drop-out P(dropout) using logistic regression P(dropout|H) = B0 + B1*H, where 'H' is the peak height or log(peak height). Produce a plot showing the model prediction. NB! There are several methods of scoring drop-out events for regression. Currently the 'MethodX', 'Method1', and 'Method2' are endorsed by the DNA commission (see Appendix B in ref 1). However, an alternative 'MethodL' is to consider the whole locus and score drop-out if any allele is missing. Explanation of the methods: Dropout - all alleles are scored according to LDT. This is pure observations and is not used for modelling. MethodX - a random reference allele is selected and drop-out is scored in relation to the the partner allele. Method1 - the low molecular weight allele is selected and drop-out is scored in relation to the partner allele. Method2 - the high molecular weight allele is selected and drop-out is scored in relation to the partner allele. MethodL - drop-out is scored per locus i.e. drop-out if any allele has dropped out. Method X/1/2 records the peak height of the partner allele to be used as the explanatory variable in the logistic regression. The locus method L also do this when there has been a drop-out, if not the the mean peak height for the locus is used. Peak heights for the locus method are stored in a separate column.

References

Peter Gill et.al., DNA commission of the International Society of Forensic Genetics: Recommendations on the evaluation of STR typing results that may include drop-out and/or drop-in using probabilistic methods, Forensic Science International: Genetics, Volume 6, Issue 6, December 2012, Pages 679-688, ISSN 1872-4973, 10.1016/j.fsigen.2012.06.002. http://www.sciencedirect.com/science/article/pii/S1872497312001354 Peter Gill, Roberto Puch-Solis, James Curran, The low-template-DNA (stochastic) threshold-Its determination relative to risk analysis for national DNA databases, Forensic Science International: Genetics, Volume 3, Issue 2, March 2009, Pages 104-111, ISSN 1872-4973, 10.1016/j.fsigen.2008.11.009. http://www.sciencedirect.com/science/article/pii/S1872497308001798

See Also

calculateDropout