National Toxicology Program

The NTP uses many different statistical procedures in the studies performed by the Program. The following overview describes the statistical procedures used in the analysis of data presented in the Technical Reports (TRs) for the NTP 2-year toxicity/carcinogenesis studies. These TRs primarily describe the findings of studies designed to evaluate the potential health effects of long-term exposure to a test agent. However, to more completely define the test agent's toxicity, these reports often include results from other types of NTP studies designed to measure exposure effects on specific biological systems. The procedures presented in this overview for these special studies only describe the statistical tests used for the data selected to be included with the Technical Report. More detailed descriptions of the statistical procedures used to evaluate the data obtained using these system-oriented protocols are provided in the references.