The noted importance of understanding glycemic control is concerning given studies estimating that only 25% of patients understand the hemoglobin A1C value (A1C). The A1C is a blood test value reflecting average blood sugars over the previous 3 months and is used as both a clinical indicator of diabetes control with guideline-set targets and as a communication format to express level of disease control to patients.Past work has demonstrated the potential effectiveness of translating poorly understood medical values, like the A1C, into more universally understood forms. We believe applications can be used to address the problem of the poorly understood A1C. This study is two-phase mixed methods approach. We will design alternative communication formats to convey the information provided by the A1C to patients and evaluate the effectiveness of these formats in improving glycemic control, increasing patient understanding of their diabetes control, and altering patient behaviors. In Phase I of the study,we will use patient feedback from semi-structured interviews with 17-25 patients with diabetes to explore the ways in which patients assess and gauge their diabetes control, as well as to elicit patient feedback on promising communication formats. Potential alternative communication formats include categories represented by color-based scales (red/yellow/green), comparisons to averages or norms, trajectories of control over time and modified medical terminology (i.e., changing the name of the test). In phase II, patients with poorly controlled diabetes will be randomized to receive information on their glycemic control through one of three study arms, A1C (control) or one of two experimental format arms (chosen based on phase I results) and the effects of these different communication formats will be evaluated.