The "Prove It Act" requires agencies to assess the economic impact of regulations on small entities. It enables small entities to petition the Small Business Administration for a review if they believe a proposed rule will impact them economically. The bill outlines the petition process, the role of the Chief Counsel, and steps for reviews. It also mandates agencies to perform regulatory analyses and publish guidance for rules affecting small entities. Non-compliance results in rule ineffectiveness. The bill introduces procedures for small entities to petition for a review of an agency's certification that a proposed rule won't have a significant economic impact. Additionally, it requires agencies to publish guidance documents for rules likely to impact small entities and adds new factors for consideration during rule reviews. If an agency fails to conduct a required review, the rule will cease to be effective. No additional funds are authorized for this Act.