What causes the broad range of reported values?
There are several reasons for the broad range of reported values. Laboratories employ a variety of techniques, different methodologies, and different calibration standards. Operator skill also plays a role. Laboratories that perform a small number of tests may have worse precision then laboratories that perform a large number of tests. If a reported value is an order of magnitude different than the rest of the results (ex. .10 vs. 1.0), than a reporting error, such as a number transposition or the wrong basis reported, may have occured.
