title: Graphs from several margins in one marginsplot in Stata
body: <p>I would like to draw margins resulting from the <code>margins</code> command in one marginsplot, but from different <code>margins</code> estimations. Important restriction: These coefficients are within the same min and max and therefore comparable. How do I do that?</p>
  
  <p>Here is a code example:</p>
  
  <pre><code>webuse nhanes2, clear
  
  tnbreg psu weight hdresult iron, iterate(5) // I am using this regression type so I stick with it here
  </code></pre>
  
  <p>I know that I can put all margins response graphs in one plot</p>
  
  <pre><code>margins, dydx(*)
  marginsplot, horizontal xline(0) yscale(reverse) recast(scatter)
  </code></pre>
  
  <p>But in fact I am running three <code>margins</code> command for each of the regressors separately, because I want to compare the effects if that regressor would vary. The code hence is</p>
  
  <pre><code>foreach var in weight hdresult iron {
    * Procedure to get the numbers for margins right
    quietly summarize `var '
    local max = r(max)
    local step = round(r(max)/6)
  
    quietly margins, at(`cvar'=(1(`step')`max'))
    marginsplot, title("") ytitle("")
  }
  </code></pre>
  
  <p>This gives me three separate files. But I want all the lines in one single figure, in different colors, of course.</p>
  
  <p>Any suggestions how to do that?</p>