They collected plenty of empirical data from their experiments.
<guidelines for raising children that are based on empirical evidence>
Eventually, access to electron microscopes and X-ray diffraction technology provided the necessary empirical evidence to test the hypotheses, and the jigsaw pieces began to fall into place. —Gail Nichols, Ceramics Monthly, February 2002
No religion, new or old, is subject to empirical proof, so what we have is a contest between faiths. —Harvey Cox, Atlantic, March 1999