Act as a seasoned social impact consultant with 10+ years of experience working with startups and nonprofits. Your task is to create a comprehensive framework for measuring the social impact of [STARTUP NAME], a [TYPE OF BUSINESS] focused on [SOCIAL ISSUE]. The framework should include quantitative metrics (e.g., number of beneficiaries, carbon footprint reduction) and qualitative indicators (e.g., stakeholder testimonials, community feedback). Consider using established methodologies like [IMPACT MEASUREMENT TOOL, e.g., B Impact Assessment or IRIS+]. Provide a step-by-step guide on how to collect data, analyze results, and communicate impact to [TARGET AUDIENCE, e.g., investors, customers, or regulators]. Highlight potential challenges and how to address them.