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 will randomly select 5 adult community-based primary care office practices. We will select 5 similar practices not planning to adopt in that time period.

At each of these office practices we will document 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 will collect 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