Clinical documentation using free text to describe a patient's medical status is an essential component of electronic health records (EHRs), and the quality of information in documents plays a critical role in clinical practice and translational research. Physicians are the primary creators of EHRs, but their clinical practices vary substantially, resulting in variations in clinical documentation. These variations can represent a source for potential bias in clinical outcomes and downstream applications using EHRs. Asthma is one example, presenting an inconsistent ascertainment process and criteria. A recent study revealed that resident physicians' knowledge of asthma diagnosis and management is relatively limited. In this study, we examined clinical documentation variations in asthma care between staff and resident physicians using individual words, topics, and asthma-related concepts in EHR clinical narratives. Additionally, we discuss potential biases in building an informatics model and further compare asthma diagnosis and outcomes between two physician groups.