Background: The implementation of hospital electronic health records software is considered a significant modernization in healthcare.Objective: The objective of this study was to evaluate the impact of electronic health records and the addition of clinical documentation specialists as a clinical support group on hospitalist documentation using case mix index (CMI) as a measurement tool. Methods:A two-group pre/postimplementation retrospective research design was used to evaluate the impact of electronic health records and clinical documentation specialists on CMI in a single 125-bed full-service community hospital in the greater Los Angeles area. All hospitalist medical records were reviewed in the pre/postphases. A total of 3,536 records were reviewed over the two phases. Phase one included a review of 1,712 hospitalist medical records before implementation of electronic health records. Phase two included a review of 1,824 hospitalist medical records after implementation of electronic health records and clinical documentation specialists. Change in CMI data were analyzed over the two phases. CMI data were treated as interval data and analyzed by parametric descriptive statistics in two phases by one-way ANOVA to compare the means between the two phases. Results:The mean CMI value for phase one was 1.65 and 1.68 for phase two. One-way ANOVA yielded no difference between the mean CMI values for the two phases (p.53). Conclusion:The implementation of electronic health records and clinical documentation specialists as a clinical support group did not make any significant difference in hospitalist documentation using CMI as a measurement tool.