You are presented with multiple paper abstracts, alongside the associated literature review and chapter titles. Given the provided information, you are going to do a literature review. Please generate a coherent literature review that synthesizes the content, draws connections between different works, highlights major findings, and identifies any gaps in the existing research.

Literature Review Title: Detecting adverse events for patient safety research: a review of current methodologies 
Chapter Title:  Adverse drug event monitors 
1. Abstract of Cited Paper (BIB001):  Objective. —To determine the excess length of stay, extra costs, and mortality attributable to adverse drug events (ADEs) in hospitalized patients. Design. —Matched case-control study. Setting. —The LDS Hospital, a tertiary care health care institution. Patients. —All patients admitted to LDS Hospital from January 1, 1990, to December 31,1993, were eligible. Cases were defined as patients with ADEs that occurred during hospitalization; controls were selected according to matching variables in a stepwise fashion. Methods. —Controls were matched to cases on primary discharge diagnosis related group (DRG), age, sex, acuity, and year of admission; varying numbers of controls were matched to each case. Matching was successful for 71% of the cases, leading to 1580 cases and 20197 controls. Main Outcome Measures. —Crude and attributable mortality, crude and attributable length of stay, and cost of hospitalization. Results. —ADEs complicated 2.43 per 100 admissions to the LDS Hospital during the study period. The crude mortality rates for the cases and matched controls were 3.5% and 1.05%, respectively (P Conclusion. —The attributable lengths of stay and costs of hospitalization for ADEs are substantial. An ADE is associated with a significantly prolonged length of stay, increased economic burden, and an almost 2-fold increased risk of death. 
2. Abstract of Cited Paper (BIB002):  CONTEXT ::: Adverse drug events (ADEs) are a significant and costly cause of injury during hospitalization. ::: ::: ::: OBJECTIVES ::: To evaluate the efficacy of 2 interventions for preventing nonintercepted serious medication errors, defined as those that either resulted in or had potential to result in an ADE and were not intercepted before reaching the patient. ::: ::: ::: DESIGN ::: Before-after comparison between phase 1 (baseline) and phase 2 (after intervention was implemented) and, within phase 2, a randomized comparison between physician computer order entry (POE) and the combination of POE plus a team intervention. ::: ::: ::: SETTING ::: Large tertiary care hospital. ::: ::: ::: PARTICIPANTS ::: For the comparison of phase 1 and 2, all patients admitted to a stratified random sample of 6 medical and surgical units in a tertiary care hospital over a 6-month period, and for the randomized comparison during phase 2, all patients admitted to the same units and 2 randomly selected additional units over a subsequent 9-month period. ::: ::: ::: INTERVENTIONS ::: A physician computer order entry system (POE) for all units and a team-based intervention that included changing the role of pharmacists, implemented for half the units. ::: ::: ::: MAIN OUTCOME MEASURE ::: Nonintercepted serious medication errors. ::: ::: ::: RESULTS ::: Comparing identical units between phases 1 and 2, nonintercepted serious medication errors decreased 55%, from 10.7 events per 1000 patient-days to 4.86 events per 1000 (P=.01). The decline occurred for all stages of the medication-use process. Preventable ADEs declined 17% from 4.69 to 3.88 (P=.37), while nonintercepted potential ADEs declined 84% from 5.99 to 0.98 per 1000 patient-days (P=.002). When POE-only was compared with the POE plus team intervention combined, the team intervention conferred no additional benefit over POE. ::: ::: ::: CONCLUSIONS ::: Physician computer order entry decreased the rate of nonintercepted serious medication errors by more than half, although this decrease was larger for potential ADEs than for errors that actually resulted in an ADE. 
3. Abstract of Cited Paper (BIB003):  The validity and cost-effectiveness of three methods for detecting medication errors were examined. A stratified random sample of 36 hospitals and skilled-nursing facilities in Colorado and Georgia was selected. Medication administration errors were detected by registered nurses (R.N.s), licensed practical nurses (L.P.N.s), and pharmacy technicians from these facilities using three methods: incident report review, chart review, and direct observation. Each dose evaluated was compared with the prescriber's order. Deviations were considered errors. Efficiency was measured by the time spent evaluating each dose. A pharmacist performed an independent determination of errors to assess the accuracy of each data collector. Clinical significance was judged by a panel of physicians. Observers detected 300 of 457 pharmacist-confirmed errors made on 2556 doses (11.7% error rate) compared with 17 errors detected by chart reviewers (0.7% error rate), and 1 error detected by incident report review (0.04% error rate). All errors detected involved the same 2556 doses. All chart reviewers and 7 of 10 observers achieved at least good comparability with the pharmacist's results. The mean cost of error detection per dose was $4.82 for direct observation and $0.63 for chart review. The technician was the least expensive observer at $2.87 per dose evaluated. R.N.s were the least expensive chart reviewers at $0.50 per dose. Of 457 errors, 35 (8%) were deemed potentially clinically significant; 71% of these were detected by direct observation. Direct observation was more efficient and accurate than reviewing charts and incident reports in detecting medication errors. Pharmacy technicians were more efficient and accurate than R.N.s and L.P.N.s in collecting data about medication errors. 
4. Abstract of Cited Paper (BIB004):  .D., FAAN, is Associate Professor and Director, Nursing Doc-torate Program (Interim), University of Colorado Health SciencesCenter, Denver.Address correspondence to Dr. Barker at the Center for PharmacyOperations and Designs, 128 Miller Hall, Auburn University, Au-burn, AL 36849-5506 (barkekn@auburn.edu).Supported by the Latiolais Leadership Program and the ASHPResearch and Education Foundation.Presented at the Measuring Medication Safety in Hospitals Con-ference, Tucson, AZ, April 8–9, 2002.Copyright © 2002, American Society of Health-System Pharma-cists, Inc. All rights reserved. 1079-2082/02/1201-2314$06.00. 
5. Abstract of Cited Paper (BIB005):  OBJECTIVE: To evaluate the frequency of medication errors using a multidisciplinary approach, to classify these errors by type, and to determine how often medication errors are associated with adverse drug events (ADEs) and potential ADEs.

Literature Review:
Several methods exist for the detection of adverse drug events. Much data has been collected through prompting nurses and pharmacists to report events, manual chart reviews BIB006 BIB004 BIB002 BIB003 and direct observation BIB005 . However, because pharmacy and laboratory data are computerized in most hospitals BIB001 , adverse drug events are particularly suitable for detection through electronic surveillance  . In this section, we will describe adverse drug event monitors. These are tools that can either search a single data source, such as pharmacy records for an antidote order, or search a combination of data sources and utilize a rule-base to detect adverse drug events.