To determine the effects of Electronic Health Record use on medication error rates in primary care office practices.

Hypothesis: Adoption of Electronic Health Records through this program will reduce medication errors

From the practices committed to implementing EHR in early 2005, we randomly selected 15 adult community-based primary care physicians. We selected 15 similar physicians in practices that were not planning to adopt in that time period.

At each of these physicians' practices we documented rates of medication errors for one week prior to the implementation of an EHR using duplicate prescription pads. Two months after the implementation in the adopting group, allowing some time for familiarization with the tool, we collected two weeks of data using computer-based information (in the adopting arm) and duplicate prescriptions (in the non-adopting arm).

Inclusion Criteria:

• All patients of physicians participating in the study

Exclusion Criteria:

• Any patients who are not part of a panel of a participating physician
• Any patients who are younger than 18 years of age
• Any patients who came in for a second visit within each data collection period