U.S. flag

An official website of the United States government

Dot gov

The .gov means it's official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

National Toxicology Program

National Toxicology Program

UPDATE NewsletterUPDATE NewsletterJanuary 2015

New OHAT Handbook for Conducting Systematic Reviews

The Office of Health Assessment and Translation (OHAT) announces release of its “Handbook for Conducting a Literature-Based Health Assessment Using OHAT Approach for Systematic Review and Evidence Integration” (https://ntp.niehs.nih.gov/go/38673). This handbook provides standard operating procedures (SOPs) for the implementation of systematic review in OHAT evaluations. The SOPs are based on (1) lessons learned from developing protocols for two case studies for implementing systematic review, (2) consideration of public comments received on systematic review during the past two years, and (3) discussions with experts at other organizations and agencies working on applying methods of systematic review to environmental health and toxicology. The handbook is a living document and will be updated as methodological practices are refined and evaluated and strategies are identified that improve the reliability, ease, and efficiency of conducting systematic reviews.

The handbook also presents OHAT’s tool for assessing study quality, or “risk of bias.” The tool applies a parallel approach to the evaluation of risk of bias for human and non-human animal studies to facilitate consideration of potential bias across evidence streams with common terminology and “domains” or areas of bias. The risk-of-bias domains and questions for experimental animal studies are based on established guidance for experimental human studies (randomized clinical trials). Detailed instructions for response are provided in a separate document available at https://ntp.niehs.nih.gov/go/38673. The risk-of-bias rating tool will be refined and updated as practices evolve and empirical evidence is developed to support risk of bias elements. OHAT is currently refining the OHAT tool to assess potential bias for in vitro or mechanistic studies.

In 2012, OHAT began activities to implement systematic review methodology in its literature-based evaluations (https://ntp.niehs.nih.gov/go/38138). Additional information about OHAT and its evaluations is available at (https://ntp.niehs.nih.gov/go/ohat).

Back to Top

The Update Newsletter is produced by NTP Office of Policy, Review, and Outreach. The text is not copyrighted and can be reprinted without permission. If you use parts of the Update Newsletter in your publication, we ask that you provide us with a copy for our records. We welcome your comments and suggestions.

Director of Office of Policy, Review, and Outreach and Editor-in-Chief: Mary Wolfe | Managing Editor: Anna Lee Mosley