OBJECTIVE: To refine the Physician Documentation Quality Instrument (PDQI) and test the validity and reliability of the 9-item version (PDQI-9). METHODS: Three sets each of admission notes, progress notes and discharge summaries were evaluated by two groups of physicians using the PDQI-9 and an overall general assessment: one gold standard group consisting of program or assistant program directors (n=7), and the other of attending physicians or chief residents (n=24). The main measures were criterion-related validity (correlation coefficients between Total PDQI-9 scores and 1-item General Impression scores for each note), discriminant validity (comparison of PDQI-9 scores on notes rated as best and worst using 1-item General Impression score), internal consistency reliability (Cronbach's alpha), and inter-rater reliability (intraclass correlation coefficient (ICC)). RESULTS: The results were criterion-related validity (r = -.678 to .856), discriminant validity (best versus worst note, t = 9.3, p = .003), internal consistency reliability (Cronbach's alphas = .87-.94), and inter-rater reliability (ICC = .83, CI = .72-.91). CONCLUSION: The results support the criterion-related and discriminant validity, internal consistency reliability, and inter-rater reliability of the PDQI-9 for rating the quality of electronic physician notes. Tools for assessing note redundancy are required to complement use of PDQI-9. Trials of the PDQI-9 at other institutions, of different size, using different EHRs, and incorporating additional physician specialties and notes of other healthcare providers are needed to confirm its generalizability.