Exploratory research synthesis--methodological considerations for addressing limitations in data quality.

Exploratory meta-analysis or research synthesis has been advocated as a way of developing important hypotheses for further study. An exploratory research synthesis was conducted on the carotid endarterectomy (CE) literature to illustrate this method. The CE scientific literature is similar to that of many other new medical interventions because it contains numerous limitations to data quality. Exploratory research synthesis of such literature necessitates a number of methodological and statistical considerations to address these limitations, including the problems of missing data, appropriate unit of analysis, nonnormal distribution of outcomes, and lack of controlled studies. Strengths and limitations of the exploratory research synthesis approach are discussed within the context of public policy decisions for assessing medical technologies.