proc iml;

/* make the original dataset available to proc iml */

  use dataset;

/* read the indepentdent variable from the original dataset */

  read all var {indepvar} into x1;

/* cread third order orthognal polynomial */

  x2 = orpol(x1, 3);

/* create a new dataset from the orthogonal polynomial */

  create orthdata from x2;
  append from x2;

quit;

/* combine the original and orthogonal polynomial datasets */

data newdata;

  set dataset;
  set orthdata;

run;

/* gives the correct model ss, f-test and rsquared values */
/* gives the incorrect orthogonal intercept estimate */

proc reg data=newdata;

  model response = col2 col3 col4;

run;

/* gives the correct orthogonal intercept estimate */
/* gives the incorrect model ss, f-test and rsquared values */

proc reg data=newdat14;

  model response = col1 col2 col3 col4 / noint;

run;