This article explores ways to measure corporate tax avoidance and its impact on policymaking. It shows that including net operating losses in the analysis can help detect tax planning strategies, but only if certain factors are considered. The study also introduces a new measure for aggressive international tax avoidance by multinational companies, revealing that some U.S. firms engage in aggressive tax planning beyond benefiting from lower tax rates. Additionally, the research highlights the connection between aggressive tax avoidance, tax havens, and manipulation of transfer prices. The findings emphasize the importance of accurate measurement and transparency in combating corporate tax avoidance.