An observational study of antibiotic prescribing behavior and the Hawthorne effect.
OBJECTIVE
To assess whether prospective, observational study procedures, including questionnaires and audio recording, are associated with different patterns of physician diagnostic decision making and antibiotic prescribing.


METHODS
(1) Survey data from a prospective observational study of treatment patterns for children with acute upper respiratory illnesses (10/96-3/97) and (2) retrospective medical record abstraction data of nonobserved encounters for the same problems occurring during (10/96-3/97) and one year after (10/97-3/98) the observational study period. Ten pediatricians in two community practices were studied.


METHODS
Patterns of diagnoses recorded in the medical record and antibiotics ordered for visits occurring outside of the observational study (same time period and one year later) were compared with the pattern of diagnoses and antibiotics ordered during the observational study.


METHODS
For the observational study (10/96-2/97), diagnosis and treatment choices were obtained from questionnaires completed by physicians immediately following the visit. For the nonstudy encounters (10/96-3/97 and 10/97-3/98), data were abstracted from medical records one year after the observational study was completed.


RESULTS
The proportion of viral cases in which an antibiotic was prescribed was 29 percentage points lower for the observational study compared to the retrospective analysis (p < .05). In one of two study sites, the proportion of cases assigned a bacterial diagnosis was 29 percentage points lower in the observational study period compared to the retrospective study (p <.05).


CONCLUSIONS
Observational study procedures including questionnaires and audio recording can affect antibiotic prescribing behavior. Future observational studies aimed at examining the frequency of inappropriate antibiotic prescribing should measure and adjust for the Hawthorne effect; without such adjustments, the results will likely underestimate the true degree of the problem. Future interventions aimed at decreasing inappropriate antibiotic prescribing should consider "harnessing" the Hawthorne effect through performance feedback to participating physicians.
Mangione-Smith
Rita
R
UCLA, Department of Pediatrics, Los Angeles, CA 90095-1752, USA.
Elliott
Marc N
MN
McDonald
Laurie
L
McGlynn
Elizabeth A
EA
D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002648:Child; D004363:Drug Utilization / Q000706:statistics & numerical data*; D015987:Effect Modifier, Epidemiologic; D006302:Health Services Research / Q000379:methods; D006801:Humans; D019370:Observation; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D011446:Prospective Studies; D012141:Respiratory Tract Infections / Q000188:drug therapy* / Q000382:microbiology / Q000821:virology; D011795:Surveys and Questionnaires; D014481:United States
D000900:Anti-Bacterial Agents