title: Fitting two coefplot in one graph using par(mfrow()) method
body: <p>I'm trying to arrange two <code>coefplot</code> objects into one graph via the <code>par(mfrow(,))</code> method, but it didn't work out. What did I do wrong? Or is that <code>coefplot</code> just doesn't work this way? What will be alternative method?
  I've referenced this <a href="https://stackoverflow.com/questions/2564258/plot-two-graphs-in-same-plot-in-r">earlier thread</a>, but I tend to think that mine is a quite different issue.</p>
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code># load the data
  dat &lt;- readRDS(url("https://www.dropbox.com/s/88h7hmiroalx3de/act.rds?dl=1"))
  
  
  #fit two models
  library(lmer4)
  
  act1.fit &lt;- glmer(act1 ~ os + education + marital + nat6 + nat5 + nat4 + nat3 + nat2 + nat1 + 
      (1 | region_id), data = action, family = binomial, control = glmerControl(optimizer = "bobyqa"),
      nAGQ = 10)
      
  action2.fit &lt;- glmer(act2 ~ os + education + marital + nat6 + nat5 + nat4 + nat3 + nat2 + nat1 + 
      (1 | region_id), data = action, family = binomial, control = glmerControl(optimizer = "bobyqa"),
      nAGQ = 10)
      
  
  # plot the two model individually
  library(coefplot)
  
  # construct coefplot objects
  
  coefplot:::buildModelCI(action1.fit)
           
  coefplot:::buildModelCI(action2.fit)
  coefplot(action2.fit, coefficients=c("nat1", "nat2", "nat3", "nat4", "nat5", "nat6"), 
           intercept = FALSE, color = "brown3")
           
  # arrange two plots in one graph
  par(mfrow=c(1,2))
  coefplot(action1.fit, coefficients=c("nat1", "nat2", "nat3", "nat4", "nat5", "nat6"), 
           intercept = FALSE, color = "brown3")
           
  coefplot(action2.fit, coefficients=c("nat1", "nat2", "nat3", "nat4", "nat5", "nat6"), 
           intercept = FALSE, color = "brown3")         
  
  # didn't work ???</code></pre>
  </div>
  </div>
  </p>