hlaCompareAllele {HIBAG} | R Documentation

## 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 <- predict(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))

[Package HIBAG version 1.18.1 Index]