Objective: The primary aims of this study were: (1) to describe variation in how physician practices and medical groups have adopted health information technology (HIT) functionalities over time; and (2) to test hypotheses about how external factors facilitated the adoption of HIT functionalities. Because of their potential policy relevance, two factors were closely examined: organizational ties; and incentives for the adoption and use of HIT.

Methods: Panel data from three national surveys of physician organizations were used to construct two cohorts of organizations: small and medium-sized physician practices with fewer than 20 physicians; and large medical groups with more than 20 physicians. For the first cohort, responses were collected largely in 2008 and 2012; for the second cohort, 2006 and 2012. Cross-sectional linear regression was used to examine factors associated with adoption by the first period, and linear regression fixed organizational effects was used to examine which organizations most frequently adopted HIT between the first and second periods.

Results: Large medical groups have generally adopted comprehensive HIT systems; small and medium-sized practices have not, but are making progress. Factor analysis showed consistent patterns of clustering in the adoption of HIT functionalities, suggesting the use of sub-indices in measuring adoption. Although the effects of organizational ties and incentives on the adoption of HIT over time were mixed, some clear trends emerged. In both periods, externally oriented HIT functionalities - those enabling information exchange - were much more likely to be adopted by small and medium-sized physician practices with formal ties to other organizations, such as health systems or independent practice associations, than independently owned practices. Additionally, incentives relevant to the adoption of HIT were frequently and strongly associated with the adoption of many HIT functionalities for organizations in both cohorts.

Conclusion: The road to comprehensive adoption and Meaningful Use of HIT may take longer than many have hoped, especially for small, independent organizations. Stronger ties across organizational boundaries may be required in order to achieve a healthcare system that is truly electronically connected.