em·pir·i·cal 
(ĕm-pîrĭ-kəl)
(ĕm-pîrĭ-kəl)adj.
1.
a. Relying on or derived from observation or experiment: empirical results that supported the hypothesis.
b. Verifiable or provable by means of observation or experiment: empirical laws.
2. Guided by practical experience and not theory, especially in medicine.
em·piri·cal·ly adv.