quietly {
  /*
     DFITS{i} is the scaled difference between the predicted 
       responses from the model constructed from all of the 
       data and the predicted responses from the model 
       constructed by setting the i-th observation aside. It 
       is similar to Cook's distance.  Unlike Cook's distance, 
       it does not look at all of the predicted values with the 
       i-th observation set aside. It looks only at the predicted 
       values for the i-th observation.      

     DFFITs that exceed (plus or minus) 2*(((`j'+1)/(`n'-`j'-1))^.5)
       are considered extreme.  j represents the number of 
       independent variables in the model.
  */
  regress  y  x 
  predict  y_dfits, dfits

  regress y1  x 
  predict y1_dfits, dfits

  regress y2  x 
  predict y2_dfits, dfits

  local j=1
  local n=10
  local dfitcrit1= 2*(((`j'+1)/(`n'-`j'-1))^.5)
  local dfitcrit2= `dfitcrit1'*-1
  local dfitcrit = round(`dfitcrit1',.001)

  #delimit ;
  graph twoway (scatter  y_dfits obs),
    title("Original Data")
    xlabel(1(1)10)
    ylabel(-1(1)2) ytick(-1(.2)2)
    yline(`dfitcrit1', lp(dash) lw(thick))
    yline(`dfitcrit2', lp(dash) lw(thick))
    name(dfits1, replace) nodraw
  ;
  #delimit cr

  #delimit ;
  graph twoway (scatter y1_dfits obs),
    title("Scenario #1")
    xlabel(1(1)10)
    ylabel(-1(1)2) ytick(-1(.2)2)
    yline(`dfitcrit1', lp(dash) lw(thick))
    yline(`dfitcrit2', lp(dash) lw(thick))
    name(dfits2, replace) nodraw
  ;
  #delimit cr

  #delimit ;
  graph twoway (scatter y2_dfits obs),
    title("Scenario #2")
    xlabel(1(1)10)
    ylabel(-1(1)2) ytick(-1(.2)2)
    yline(`dfitcrit1', lp(dash) lw(thick))
    yline(`dfitcrit2', lp(dash) lw(thick))
    name(dfits3, replace) nodraw
  ;
  #delimit cr

  #delimit ;
  graph combine dfits1 dfits2 dfits3,
    title("Plot of DFITS")
    note("|DFITS| > `dfitcrit'")
    name(DFITS, replace)
  ;
  #delimit cr

  drop *dfit*
}