overall aim of the project was to create a clinical practice guideline with recommendations for AKI using an evidence-based approach. After topics and relevant clinical questions were identified, the pertinent scientific literature on those topics was systematically searched and summarized. Group member selection and meeting process The KDIGO Co-Chairs appointed the Co-Chairs of the Work Group, who then assembled the Work Group to be responsible for the development of the guideline. The Work Group consisted of domain experts, including individuals with expertise in nephrology, critical care medicine, internal medicine, pediatrics, cardiology, radiology, infectious diseases and epidemiology. For support in evidence review, expertise in methods, and guideline development, the NKF contracted with the Evidence Review Team (ERT) based primarily at the Tufts Center for Kidney Disease Guideline Development and Implementation at Tufts Medical Center in Boston, Massachusetts, USA. The ERT consisted of physician-methodologists with expertise in nephrology and internal medicine, and research associates and assistants. The ERT instructed and advised Work Group members in all steps of literature review, critical literature appraisal, and guideline development. The Work Group and the ERT collaborated closely throughout the project. The Work Group, KDIGO Co-Chairs, ERT, liaisons, and NKF support staff met for four 2-day meetings for training in the guideline development process, topic discussion, and consensus development. Evidence selection, appraisal, and presentation We first defined the topics and goals for the guideline and identified key clinical questions for review. The ERT performed literature searches, organized abstract and article screening, coordinated methodological and analytic processes of the report, defined and standardized the search methodology, performed data extraction, and summarized the evidence. The Work Group members reviewed all included articles, data extraction forms, summary tables, and evidence profiles for accuracy and completeness. The four major topic areas of interest for AKI included: i) definition and classification; ii) prevention; iii) pharmacologic treatment; and iv) RRT. Populations of interest were those at risk for AKI (including those after intravascular contrast-media exposure, aminoglycosides, and amphotericin) and those with or at risk for AKI with a focus on patients with sepsis or trauma, receiving critical care, or undergoing cardiothoracic surgery. We excluded studies on AKI from rhabdomyolysis, specific infections, and poisoning or drug overdose. Overall, we screened 18 385 citations. Outcome selection judgments, values, and preferences We limited outcomes to those important for decision making, including development of AKI, need for or dependence on RRT, and all-cause mortality. When weighting the evidence across different outcomes, we selected as the ‘‘crucial’’ outcome that which weighed most heavily in the assessment of the overall quality of evidence. Values and preferences articulated by the Work Group included: i) a desire to be inclusive in terms of meeting criteria for AKI; ii) a progressive approach to risk and cost such that, as severity increased, the group put greater value on possible effectiveness of strategies, but maintained high value for avoidance of harm; iii) intent to guide practice but not limit future research. Grading the quality of evidence and the strength of recommendations The grading approach followed in this guideline is adopted from the GRADE system.40,41 The strength of each recommendation is rated as level 1 which means ‘‘strong’’ or level 2 which means ‘‘weak’’ or discretionary. The wording corresponding to a level 1 recommendation is ‘‘We recommend y should’’ and implies that most patients should receive the course of action. The wording for a level 2 recommendation is ‘‘We suggest y might’’ which implies that different choices will be appropriate for different patients, with the suggested course of action being a reasonable choice in many patients. In addition, each statement is assigned a grade for the quality of the supporting evidence, A (high), B (moderate), C (low), or D (very low). Table 1 shows the implications of the guideline grades and describes how the strength of the recommendations should be interpreted by guideline users. Furthermore, on topics that cannot be subjected to systematic evidence review, the Work Group could issue statements that are not graded. Typically, these provide guidance that is based on common sense, e.g., reminders of the obvious and/or recommendations that are not sufficiently specific enough to allow the application of evidence. The GRADE system is best suited to evaluate evidence on comparative effectiveness. Some of our most important guideline topics involve diagnosis and staging or AKI, and here the Work Group chose to provide ungraded statements. These statements are indirectly supported by evidence on risk relationships and resulted from unanimous consensus of the Work Group. Thus, the Work Group feels they should not be viewed as weaker than graded recommendations. http://www.kidney-international.org chapter 1.2 & 2012 KDIGO Kidney International Supplements (2012) 2, 13–18 17 SPONSORSHIP KDIGO