Ensuring the accuracy and integrity of MIS reports, especially when dealing with large datasets, involves several key practices. Firstly, I always start by validating the data sources to ensure that the information being used is reliable and up-to-date. I make use of Google Sheets' data validation features to prevent incorrect data entry. Additionally, I utilize formulas and pivot tables to cross-check data for consistency and identify any discrepancies. Regular audits of the data are conducted to catch errors early. I also ensure that all calculations and formulas are double-checked for accuracy. Collaborating with team members to verify data points and report findings is another crucial step. Lastly, maintaining a clear documentation process helps in tracking changes and understanding the data flow, which is essential for maintaining data integrity over time.