PrecisionGoal is an option for various numerical operations which specifies how many effective digits of precision should be sought in the final result.
PrecisionGoal->Automatic normally yields a precision goal equal to half the setting for WorkingPrecision.
PrecisionGoal->Infinity specifies that precision should not be used as the criterion for terminating the numerical procedure. AccuracyGoal is typically used in this case.
Even though you may specify PrecisionGoal->n, the results you get may sometimes have much less than n-digit precision.