BSR has been conducting human rights due diligence with companies since our founding, a little more than 20 years ago. Over the past two years, we have worked with companies in multiple industries conducting human rights impact assessments (HRIAs) that align with the Guiding Principles on Business and Human Rights. This report is intended to capture the lessons we have learned and to share our eight guidelines for conducting effective HRIAs, as well as step-by-step guidance on the four levels of HRIAs: corporate, country, site, and product.