empirical

em|piri|cal /ɪmp'ɪrɪkəl/
[ADJ] usu ADJ n
Empirical evidence or study relies on practical experience rather than theories.
There is no empirical evidence to support his thesis.
empirically [ADV] usu ADV adj/-ed, ADV after v
...empirically based research...
They approached this part of their task empirically.