The impact of the work environment on clinical performance and outcomes is receiving renewed interest by health systems researchers, health care administrators, and policy makers (IOM Committee on Quality of Health Care in America 2001; Shortell 2002; Shortell and Selberg 2002). A growing body of literature derived from research in large health care settings, such as hospitals and large multispecialty group practices, suggests that better health outcomes are associated with particular organizational attributes (Shortell and LoGerfo 1981; Shortell 1985, 1990, 2002; Davies and Ware 1988; Shortell, O'Brien et al. 1994; Shortell, Zimmerman et al. 1994; Shortell et al. 1998; Mitchell and Shortell 1997; Davies and Nutley 2000; Donaldson et al. 2000; Ferlie and Shortell 2001). Similar studies within primary care have the potential to impact a broader spectrum of the American population. In a given year most Americans visit a primary care physician (Benson and Marano 1994), with more than a quarter of these visits to family medicine practices (Woodwell 1999). Primary care practices, including family medicine, general internal medicine, and pediatric practices, are unique among health providers in that they must serve as the front line for large variety of health care needs, from prevention to identification of disease and illness to the treatment of ailments or referral to specialists. To understand the impact of organizational attributes of primary care practices on delivery of patient care, one first needs to understand the attributes of these typically small medical providers and develop a method for measuring these attributes. A key element of a practice's ability to maintain and improve quality of care for their patients is their ability to adapt to the evolving understanding of medicine, to demands for enhanced clinical performance, and to changes in the larger health care management system. While general models of change have been proposed (Senge 1990, 1994; Rogers 1995), these models have typically not incorporated the features unique to primary care practices. One exception is the primary care change model recently described by Cohen et al. (2004) that includes four interdependent elements that determine a practice's capacity for sustainable change. This model emerged from three federally funded studies, two descriptive studies, the Direct Observation of Primary Care (DOPC) study (Crabtree et al. 1998; Miller et al. 1998) and Prevention & Competing Demands in Primary Care (PC Miller et al. 1998; Tallia et al. 2003), and one intervention study, the Study to Enhance Prevention by Understanding Practice (STEP-UP) (Goodwin et al. 2001; Cohen et al. 2004). The model identifies clinician and staff characteristics, particularly their interrelationships, as important in distinguishing the between practices' abilities to improve their rates of delivery of prevention services. Of the four elements described by Cohen et al. (motivation of key stakeholders, resources for change, outside motivators, and opportunities for change), resources for change best describes organizational characteristics that a practice must have to modify not only its technical aspects, but also its values and beliefs regarding itself as an organization. The resources for change element includes internal resources such as relationships among practice members, leadership and decision-making approaches, communication and perception of competing demands. Information management and management infrastructure, are also facets of the internal resources for change element. Measurement tools exist for assessing important organizational attributes of larger health systems, such as hospitals (Shortell 1985; Shortell et al.1991, 2000; Jennings and Westfall 1994; Nabitz et al. 2000; Weeks et al. 2000; Meyer and Collier 2001; Nordhaus-Bike 2001; Goldstein and Schweikhart 2002). These attributes include: (1) leadership that engages a diversity of perspectives and shares critical information in order to enhance problem solving processes; (2) a culture that fosters openness, connectedness, and learning; (3) relationships that foster communication and collaboration; (4) management functions that describe presence of diverse structural components and processes such as fiscal, material, clinical, recognition, and feedback, and strategic planning; and (5) information mastery that includes the access and use of information that supports learning and problem solving activities (Shortell et al. 1998; Davies and Nutley 2000; Donaldson et al. 2000; Ferlie and Shortell 2001). The first three of these attributes, in particular, were also identified by Cohen et al. (2004) as internal resources that are needed to create and sustain change (Cohen et al. 2004) in the primary care practice. However, a systematic tool to measure these attributes in primary care practices has not been developed. Because these practices are much smaller and have much more limited resources than hospitals and other larger health systems, instruments for measuring attributes of larger health systems are not expected to describe and differentiate between primary care practices well. As such, an instrument must be created specifically for use in the primary care practice. This study aims to develop an instrument to measure organizational attributes of primary care practices and to evaluate the measurement properties of this newly developed instrument. The instrument, intended to be a survey of clinicians, nurses and staff within the practice, seeks to measure some facets of resources for change, including relationships among practice members, leadership and decision-making approaches, communication, and perception of competing demands. The other facets, specifically information management and management infrastructure, are thought to be better addressed at the practice level by one or two key members of the practice, for example the office manager or medical director. This instrument is developed based on the experience of investigators in family medicine, internal medicine, and pediatric practices; however, its use will be evaluated within family medicine practices. It was hypothesized that this instrument's items would measure internal resources for change and be able to sort practices according to the strength of their available internal resources.