The Skills, Confidence, and Preparedness Index (SCPI) is an electronic tool designed to assess three dimensions (knowledge, confidence, and preparedness) in a clinically relevant measure, with immediate feedback to guide the individualization of patient education. This study sought to assess the validity and reliability of the final SCPI generation, its relevance to glycemia, and its responsiveness to patient education.In Part 1, patients with type 1 and type 2 diabetes were recruited from specialist clinics over a 6-month period and completed the 23-item SCPI using a tablet. In Part 2, participants also underwent a diabetes self-management education (DSME) program. Baseline SCPI score was used to guide the DSME, and SCPI and glycemia were assessed at completion.In total, 423 patients met inclusion criteria and 405 had evaluable data. SCPI scores were found to have a high degree of validity, internal consistency, and test-retest reliability, with no floor or ceiling effects. Scoring was negatively correlated with HbA (type 1 diabetes: = -0.26, = 0.001; type 2 diabetes: = -0.20, = 0.004). In 51 participants who underwent a DSME intervention (6.4 ± 0.6 visits over a mean 3.4 ± 0.8 months), mean HbA improvement was 1.2 ± 0.2% (13.1 ± 2.2 mmol/mol, < 0.0001). Total SCPI score and each subscore improved in parallel.The SCPI tool is a quick and easy-to-use measurement of three domains: skills, confidence, and preparedness. The instant scoring and feedback and its relationship to glycemic control should improve the efficiency and quality of individualizing care in the diabetes clinic.