srtBayes {eefAnalytics}R Documentation

Bayesian Analysis of Simple Randomised Education Trials (SRT) using Bayesian Linear Regression Model with Vague Priors.

Description

srtBayes performs Bayesian multilevel analysis of Simple Randomised Education Trials (SRT), utilising vague priors and JAGS language to fit the model. This can also be used with schools as fixed effects.

Usage

srtBayes(
  formula,
  intervention,
  baseln,
  nsim = 2000,
  data,
  alpha = 0.05,
  digits = 3,
  threshold = 1:10/10,
  condopt,
  uncopt,
  ...
)

Arguments

formula

The model to be analysed is of the form y~x1+x2+.... Where y is the outcome variable and Xs are the independent variables.

intervention

A string variable specifying the "intervention variable" as appearing in the formula and the data. See example below.

baseln

A string variable allowing the user to specify the reference category for intervention variable. When not specified, the first level will be used as a reference.

nsim

number of MCMC iterations per chain. Default is 2000.

data

Data frame containing the data to be analysed.

alpha

significant level, default alpha = 0.05.

digits

number of decimal places, by default digits=3

threshold

a scalar or vector of pre-specified threshold(s) for estimating Bayesian posterior probability such that the observed effect size is greater than or equal to the threshold(s).

condopt

additional arguments of jags to be passed only to the conditional model specification (for example, defining priors only for the conditional model, etc.).

uncopt

additional arguments of jags to be passed only to the unconditional model specification (for example, defining priors only for the unconditional model, etc.).

...

Common additional arguments of jags to be passed to both the conditional and unconditional model specifications

Value

S3 object; a list consisting of

Examples

if(interactive()){

  data(mstData)

  ########################################################
  ## Bayesian analysis of simple randomised trials      ##
  ########################################################

  output <- srtBayes(Posttest~ Intervention+Prettest,
                     alpha = 0.2,
                     digits=4,
                     intervention="Intervention",
                     nsim=10000,
                     data=mstData)

  ### Fixed effects
  beta <- output$Beta
  beta

  ### Effect size
  ES1 <- output$ES
  ES1

  ### Effect size
  ES2 <- output$Unconditional$ES
  ES2

  ## Covariance matrix
  covParm1 <- output$sigma2
  covParm1


  ## Unconditional Covariance matrix
  covParm2 <- output$Unconditional$sigma2
  covParm2


  ## Prob ES
  ProbES1 <- output$ProbES
  ProbES1


  ## Prob  based on Unconditional ES
  ProbES2 <- output$Unconditional$ProbES
  ProbES2


  ### plot posterior probability of an effect size to be bigger than a pre-specified threshold

  plot(output,group=1)


}

[Package eefAnalytics version 1.1.5 Index]