hlaCompareAllele: Evaluate prediction accuracies

In zhengxwen/HIBAG: HLA Genotype Imputation with Attribute Bagging

Evaluate prediction accuracies

Description

To evaluate the overall accuracy, sensitivity, specificity, positive predictive value, negative predictive value.

Usage

hlaCompareAllele(TrueHLA, PredHLA, allele.limit=NULL, call.threshold=NaN,
    match.threshold=NaN, max.resolution="", output.individual=FALSE,
    verbose=TRUE)

Arguments

TrueHLA	an object of hlaAlleleClass, the true HLA types
PredHLA	an object of hlaAlleleClass, the predicted HLA types
allele.limit	a list of HLA alleles, the validation samples are limited to those having HLA alleles in allele.limit, or NULL for no limit. allele.limit could be character-type, hlaAttrBagClass or hlaAttrBagObj
call.threshold	the call threshold for posterior probability, i.e., call or no call is determined by whether prob >= call.threshold or not
match.threshold	the matching threshold for SNP haplotype similiarity, e.g., use 1% quantile of matching statistics of a training model
max.resolution	"2-digit", "4-digit", "6-digit", "8-digit", "allele", "protein", "2", "4", "6", "8", "full" or "": "allele" = "2-digit", "protein" = "4-digit", "full" and "" indicating no limit on resolution
output.individual	if TRUE, output accuracy for each individual
verbose	if TRUE, show information

Value

Return a list(overall, confusion, detail), or list(overall, confusion, detail, individual) if output.individual=TRUE.

overall (data.frame):

total.num.ind	the total number of individuals
crt.num.ind	the number of individuals with correct HLA types
crt.num.haplo	the number of chromosomes with correct HLA alleles
acc.ind	the proportion of individuals with correctly predicted HLA types (i.e., both of alleles are correct, the accuracy of an individual is 0 or 1.)
acc.haplo	the proportion of chromosomes with correctly predicted HLA alleles (i.e., the accuracy of an individual is 0, 0.5 or 1, since an individual has two alleles.)
call.threshold	call threshold, if it is NaN, no call threshold is executed
n.call	the number of individuals with call
call.rate	overall call rate

confusion (matrix): a confusion matrix.

detail (data.frame):

allele	HLA alleles
train.num	the number of training haplotypes
train.freq	the training haplotype frequencies
valid.num	the number of validation haplotypes
valid.freq	the validation haplotype frequencies
call.rate	the call rates for HLA alleles
accuracy	allele accuracy
sensitivity	sensitivity
specificity	specificity
ppv	positive predictive value
npv	negative predictive value
miscall	the most likely miss-called alleles
miscall.prop	the proportions of the most likely miss-called allele in all miss-called alleles

individual (data.frame):

sample.id	sample id
true.hla	the true HLA type
pred.hla	the prediction of HLA type
accuracy	accuracy, 0, 0.5, or 1

Author(s)

Xiuwen Zheng

See Also

hlaAttrBagging, predict.hlaAttrBagClass, hlaReport

Examples

# make a "hlaAlleleClass" object
hla.id <- "A"
hla <- hlaAllele(HLA_Type_Table$sample.id,
    H1 = HLA_Type_Table[, paste(hla.id, ".1", sep="")],
    H2 = HLA_Type_Table[, paste(hla.id, ".2", sep="")],
    locus=hla.id, assembly="hg19")

# divide HLA types randomly
set.seed(100)
hlatab <- hlaSplitAllele(hla, train.prop=0.5)
names(hlatab)
# "training"   "validation"
summary(hlatab$training)
summary(hlatab$validation)

# SNP predictors within the flanking region on each side
region <- 500   # kb
snpid <- hlaFlankingSNP(HapMap_CEU_Geno$snp.id, HapMap_CEU_Geno$snp.position,
    hla.id, region*1000, assembly="hg19")
length(snpid)  # 275

# training and validation genotypes
train.geno <- hlaGenoSubset(HapMap_CEU_Geno,
    snp.sel=match(snpid, HapMap_CEU_Geno$snp.id),
    samp.sel=match(hlatab$training$value$sample.id,
    HapMap_CEU_Geno$sample.id))
test.geno <- hlaGenoSubset(HapMap_CEU_Geno,
    samp.sel=match(hlatab$validation$value$sample.id,
    HapMap_CEU_Geno$sample.id))

# train a HIBAG model
set.seed(100)
model <- hlaAttrBagging(hlatab$training, train.geno, nclassifier=4,
    verbose.detail=TRUE)
summary(model)

# validation
pred <- hlaPredict(model, test.geno)
# compare
(comp <- hlaCompareAllele(hlatab$validation, pred, allele.limit=model,
    call.threshold=0))
(comp <- hlaCompareAllele(hlatab$validation, pred, allele.limit=model,
    call.threshold=0.5))

zhengxwen/HIBAG documentation built on April 16, 2024, 8:41 a.m.