Background and aims: Unnecessary variation in the delivery of patient care is well documented in the medical literature; evidence-based clinical practice is critical for improving the quality of care. Clinical decision support systems (CDSS) are promising tools for improving the systematic integration of evidence into clinical practice. This study evaluated a CDSS in a domain of care that had not yet been explored—namely, decision support for venous catheter selection. This dissertation study aimed to (1) evaluate the effect of this CDSS on provider ordering behavior before and after implementation and explore the differential impact of this tool by provider type and service and (2) identify organizational, individual, usability, and workflow factors that impact CDSS acceptance by physicians and advanced practice nurses and to elicit information about the impact of this system on communication between providers and the nurse-led vascular access team. Methods: This was a multi-method study. Aim one was single group pre-post analysis of longitudinal data. Variables included those related to patient and provider level factors. The main analysis was conducted with linear regression models with random effects to account for clustering of data. We conducted semi-structured interviews for aim two and use conventional qualitative content analysis to identify themes. Results: We found mixed results in the impact of the CDSS on provider ordering behavior. While the CDSS did not have an impact on the number of venous catheters ordered, we saw a statistically and clinically significant decrease in the proportion of double lumen catheters ordered. Findings for the qualitative aim showed that the CDSS improved process efficiency and inter-professional communication. We found that it also facilitated education for evidence based practice for novice providers. Discussion: This dissertation study showed a clear impact of the CDSS on double lumen catheter ordering, which has implications for patient outcomes. Furthermore, we found impacts by provider type. Additional work is needed to evaluate this CDSS in other settings and to further assess differential impacts by provider type.