title: Issue creating Likert-scale plots in r
body: <p>I'm trying to plot data from a study that used a Likert-scale measurement. I am using the <a href="https://github.com/jbryer/likert" rel="nofollow noreferrer">'Likert' package</a>. The problem I have occurs when I try to group the data in the plot. For illustratation, I will demonstrate using a dataset that is used in many of the online demos such as<br>
  <a href="http://jason.bryer.org/likert/" rel="nofollow noreferrer">this one</a></p>
  
  <p>When I run the code, I want/expect a graph that looks like this (notice that the bar plots are organised in a nice ordered sequence from 'strongly disagree' to 'strongly agree'):
  <a href="https://i.stack.imgur.com/6AXAF.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/6AXAF.png" alt="enter image description here"></a></p>
  
  <p>When I run the following code, I get a graph where the order is confused; mainly 'agree' and 'strongly agree' are swapped around. Can anyone shed some light as to why this might be happening and how I can fix it? Any help would be greatly appreciated. </p>
  
  <pre><code>require(likert)
  library(plyr)
  
  ##### import built-in data
  data(pisaitems)
  
  # extract data for analysis
  items24 &lt;- pisaitems[,substr(names(pisaitems), 1,5) == 'ST24Q']
  
  # rename cols
  items24 &lt;- rename(items24, c(
    ST24Q01="I read only if I have to.",
    ST24Q02="Reading is one of my favorite hobbies.",
    ST24Q03="I like talking about books with other people.",
    ST24Q04="I find it hard to finish books.",
    ST24Q05="I feel happy if I receive a book as a present.",
    ST24Q06="For me, reading is a waste of time.",
    ST24Q07="I enjoy going to a bookstore or a library.",
    ST24Q08="I read only to get information that I need.",
    ST24Q09="I cannot sit still and read for more than a few minutes.",
    ST24Q10="I like to express my opinions about books I have read.",
    ST24Q11="I like to exchange books with my friends."))
  
  # capture Likert data by group
  l24g &lt;- likert(items24[,1:11], grouping=pisaitems$CNT)
  
  # plot
  plot(l24g)
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/sKjM0.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/sKjM0.png" alt="enter image description here"></a></p>