tly includes newspaper and journal articles though the authors also provide the results of at least two surveys carried out by highly credible organizations such as Kaiser Family Foundation and Joint Commission on Accreditation of Healthcare Organizations.2. The lack of detailed literature review barely allows to somehow link Aiken’s findings to a wider framework of information available in the field. Although the study’s objective (to determine the association between the patient-to-nurse ration and patient mortality, deaths following complications, and factors related to nurse retention) clearly suggests that the authors’ intention is to reveal and detail the root causes of the recent nurse shortage, absence of a serious literature review does not make it possible to find out whether this objective is an actual extension of the existing knowledge base. By contrast, solid literature enables the reader to identify gaps in the relevant research and properly justify the need for another study in this field.3. Although the authors do not state any specific rationale for the study there is simply no need to do so: the rationale is absolutely clear. The issue of nurse shortage is not new to the scholarly literature through Aiken and colleagues provide only a very brief insight into the existing publications. A growing body of empirical evidence is available to support the notion that the effectiveness of the health care system largely depends upon the nurses. At the same time, there are few studies that attempt to clarify the root relationships between nurse retention rates and job satisfaction and burnout. Therefore, expanding the body of knowledge on this phenomenon is an important task building opportunities for better performance in hospitals.1. The authors provide no operational definitions of the independent and dependent variables under study. However, the lack of definitions does not negatively affect the study: the variables are simple and do not necessarily require definitions.