Towards the end of 2012, The Society of Toxicologic Pathology (STP) sponsored a working group to address the concept of “Adversity” in regulatory documents through the auspices of the Scientific and Regulatory Policy Committee. Confusion about identifying an “adverse” effect leading to the designation of a “No Adverse Effect Level (NOAEL)” in nonclinical studies has too frequently resulted in misunderstandings and unnecessarily contentious situations. Inconsistent approaches and opinions related to communicating adverse effects in nonclinical study reports, summary documents, and data tables can impede risk assessment and management, and unnecessarily delay the progression of beneficial drugs undergoing clinical evaluation. The STP believed that agreement or standardization of basic principles related to “adversity” and “NOAEL” could vastly improve the understanding of nonclinical study results for clinicians and regulators.