During 1992 and 1993, the overall number of ERNS and HMIS events decreased from 1,873 to 1,329.
A total of 1,579 ERNS and HMIS incidents were classified as potential HSEES events.
ERNS and HMIS are passive reporting systems, while HSEES is an active system.
Most duplicate records found in the ERNS and HMIS databases occurred because of the nature of reporting in ERNS.
The existence of 161 unverified events in the ERNS and HMIS incidents can be attributed to differences in event definitions between the three systems.
The number of ERNS and HMIS reports decreased by 543 during the same period.
0%) of the 3,202 ERNS and HMIS events were missed by the HSEES system, only 141 (4.
Efforts to evaluate these ERNS and HMIS events were difficult, and found that the number of these events meeting the existing HSEES surveillance definition is very low.
While there are reporting discrepancies between the ERNS, HMIS, and HSEES surveillance databases, that fact should not invalidate the usefulness of any of the systems.