Program analyses and optimization of Java programs require reference information that determines the instances that may be accessed through dereferences. Reference information can be computed using reference analysis. This paper presents a set of studies that evaluate the precision of some existing approaches for identifying instances and for computing reference information in a reference analysis. The studies use dynamic reference information collected during run-time as a lower bound approximation to the precise reference information. The studies measure the precision of an existing approach by comparing the information computed using the approach with the lower bound approximation. The paper also presents case studies that attempt to identify the cases under which an existing approach is not effective. The presented studies provide information that may guide the usage of existing reference analysis techniques and the development of new reference analysis techniques.