An IBM Cognos BI Developer designs, develops, and maintains business intelligence (BI) solutions using IBM Cognos. They create reports and dashboards to meet business requirements and generate insights from data. Their duties include data modeling, creating and managing data warehouses, and conducting data analysis. They troubleshoot and resolve BI issues while ensuring data accuracy and integrity. They also work with stakeholders to understand their needs, translate them into technical requirements, and provide support in decision-making processes. Furthermore, they may provide training to users, ensuring they can effectively use the BI tools and understand the generated reports.