Multivariate tests on results from dream()

Evaluate multivariate tests on results from dream() using vcov() to compute the covariance between estimated regression coefficients across multiple responses. A joint test to see if the coefficients are jointly different from zero is performed using meta-analysis methods that account for the covariance.

Usage

mvTest(
  fit,
  vobj,
  features,
  coef,
  method = c("FE.empirical", "FE", "RE2C", "tstat", "hotelling", "sidak", "fisher"),
  shrink.cov = TRUE,
  BPPARAM = SerialParam(),
  ...
)

# S4 method for MArrayLM,EList,vector
mvTest(
  fit,
  vobj,
  features,
  coef,
  method = c("FE.empirical", "FE", "RE2C", "tstat", "hotelling", "sidak", "fisher"),
  shrink.cov = TRUE,
  BPPARAM = SerialParam(),
  ...
)

# S4 method for MArrayLM,EList,missing
mvTest(
  fit,
  vobj,
  features,
  coef,
  method = c("FE.empirical", "FE", "RE2C", "tstat", "hotelling", "sidak", "fisher"),
  shrink.cov = TRUE,
  BPPARAM = SerialParam(),
  ...
)

# S4 method for MArrayLM,EList,list
mvTest(
  fit,
  vobj,
  features,
  coef,
  method = c("FE.empirical", "FE", "RE2C", "tstat", "hotelling", "sidak", "fisher"),
  shrink.cov = TRUE,
  BPPARAM = SerialParam(),
  ...
)

# S4 method for mvTest_input,ANY,ANY
mvTest(
  fit,
  vobj,
  features,
  coef,
  method = c("FE.empirical", "FE", "RE2C", "tstat", "hotelling", "sidak", "fisher"),
  shrink.cov = TRUE,
  BPPARAM = SerialParam(),
  ...
)

# S4 method for MArrayLM,matrix,ANY
mvTest(
  fit,
  vobj,
  features,
  coef,
  method = c("FE.empirical", "FE", "RE2C", "tstat", "hotelling", "sidak", "fisher"),
  shrink.cov = TRUE,
  BPPARAM = SerialParam(),
  ...
)

Arguments

fit

MArrayLM or MArrayLM2 returned by dream()

vobj

matrix or EList object returned by voom()

features

a) indeces or names of features to perform multivariate test on, b) list of indeces or names. If missing, perform joint test on all features.

coef

name of coefficient or contrast to be tested

method

statistical method used to perform multivariate test. See details. 'FE' is a fixed effect test that models the covariance between coefficients. 'FE.empirical' use compute empirical p-values by sampling from the null distribution and fitting with a gamma. 'RE2C' is a random effect test of heterogeneity of the estimated coefficients that models the covariance between coefficients, and also incorporates a fixed effects test too. 'tstat' combines the t-statistics and models the covariance between coefficients. 'hotelling' performs the Hotelling T2 test. 'sidak' returns the smallest p-value and accounting for the number of tests. 'fisher' combines the p-value using Fisher's method assuming independent tests.

shrink.cov

shrink the covariance matrix between coefficients using the Schafer-Strimmer method

BPPARAM

parameters for parallel evaluation

...

other arugments

Value

Returns a data.frame with the statistics from each test, the pvalue from the test, n_features, method, and lambda from the Schafer-Strimmer method to shrink the estimated covariance. When shrink.cov=FALSE, lambda = 0.

Details

See package remaCor for details about the remaCor::RE2C() test, and see remaCor::LS() for details about the fixed effect test. When only 1 feature is selected, the original p-value is returned and the test statistic is set to NA.

For the "RE2C" test, the final test statistic is the sum of a test statistic for the mean effect (stat.FE) and heterogeneity across effects (stat.het). mvTest() returns 0 if stat.het is negative in extremely rare cases.

Examples

# library(variancePartition)
library(edgeR)
library(BiocParallel)

data(varPartDEdata)

# normalize RNA-seq counts
dge <- DGEList(counts = countMatrix)
dge <- calcNormFactors(dge)

# specify formula with random effect for Individual
form <- ~ Disease + (1 | Individual)

# compute observation weights
vobj <- voomWithDreamWeights(dge[1:20, ], form, metadata)

# fit dream model
fit <- dream(vobj, form, metadata)
fit <- eBayes(fit)

# Multivariate test of features 1 and 2
mvTest(fit, vobj, 1:2, coef = "Disease1")
#>        beta        se     stat       pvalue n_features lambda       method
#> 1 0.9301722 0.1325913 7.015336 7.022132e-10          2   0.01 FE.empirical

# Test multiple sets of features
lst <- list(a = 1:2, b = 3:4)
mvTest(fit, vobj, lst, coef = "Disease1", BPPARAM = SnowParam(2))
#>   ID      beta        se     stat       pvalue n_features lambda       method
#> 1  a 0.9301722 0.1325913 7.015336 7.420512e-10          2   0.01 FE.empirical
#> 2  b 0.9005393 0.1284976 7.008220 6.457419e-09          2   0.01 FE.empirical