Study objective: The phenomenon of altered behavior or performance resulting from awareness of being a part of an experimental study has been termed the "Hawthorne effect." Prehospital studies generally involve paramedics or are designed to use data collected by paramedics. Our objective was to determine whether paramedic performance, as measured by frequency of documentation, can be modified by (1) written notification of the importance of documentation, (2) written notification of a research project involving paramedic documentation, or (3) written notification of a quality-improvement audit of paramedic documentation.

Design: Prospective, sequential intervention study with five study phases. Setting: Urban, all-advanced life support public utility model emergency medical services system with 55,000 emergency calls per year. Participants: One hundred forty-five paramedics who completed all ambulance run reports from August 1992 to May 1993. Results: A total of 30,828 run reports was entered into the study. Baseline undocumented parameters ranged from 3.7% to 6.5%. Compared with baseline, a memo to heighten awareness (phase 2) did not alter documentation (P ≥.08). A medication study memo (phase 3) improved medication documentation (P =.0005) and allergies documentation (P =.037). A quality-improvement audit memo (phase 4) improved documentation of all parameters (P ≤.001). Conclusion: The Hawthorne effect occurs in prehospital research. It does not require direct observation, nor does it require direct feedback. However, it may require a perceived demand for performance. The Hawthorne effect must be considered in the design of prehospital studies and interpretation of data collected by paramedics. [Campbell JP, Maxey VA, Watson WA: Hawthorne effect: Implications for prehospital research. Ann Emerg Med November 1995;26:590-594.]