IVW-class {MRZero}

IVW Class

Description

An object containing the estimate produced using the inverse-variance weighted (IVW) method as well as various statistics.

Slots

Model

The model used for estimation: random-effects ("random") or fixed-effect ("fixed"). The default option ("default") is to use a fixed-effect model when there are three or fewer genetic variants, and a random-effects model when there are four or more. The (multiplicative) random-effects model allows for heterogeneity between the causal estimates targeted by the genetic variants by allowing over-dispersion in the regression model. Under-dispersion is not permitted (in case of under-dispersion, the residual standard error is set to 1, as in a fixed-effect analysis).

Exposure

The name of the exposure variable.

Outcome

The name of the outcome variable.

Correlation

The matrix of correlations between genetic variants.

Robust

Whether robust regression was used in the regression model relating the genetic associations with the outcome and those with the exposure.

Penalized

Whether weights in the regression model were penalized for variants with heterogeneous causal estimates.

Estimate

The causal point estimate from the inverse-variance weighted method.

StdError

The standard error associated with Estimate.

CILower

The lower bound of the confidence interval for Estimate based on StdError.

CIUpper

The upper bound of the confidence interval for Estimate based on StdError.

Alpha

The significance level used in constructing the confidence interval (default is 0.05).

Pvalue

P-value associated with the causal estimate.

SNPs

The number of SNPs that were used in the calculation.

RSE

The estimated residual standard error from the regression model.

Heter.Stat

Heterogeneity statistic (Cochran's Q statistic) and associated p-value: the null hypothesis is that all genetic variants estimate the same causal parameter; rejection of the null is an indication that one or more variants may be pleiotropic.

Fstat

An approximation of the first-stage F statistic for all variants based on the summarized data.