Excel data validation is the cheapest insurance in any financial model: it controls what goes into your input cells before a bad entry breaks something. This episode shows how to build drop-down menus, scenario switches and input rules that keep a model clean when someone else opens it.

In this episode:

• Drop-down menus for a Base / Upside / Downside scenario switch
• Keeping lists on a dedicated Lists sheet with named ranges
• Input messages, error alerts and custom validation rules
• Dependent drop-downs with INDIRECT and rejecting duplicates with COUNTIF
• Circle Invalid Data: auditing an inherited model in seconds

📖 Full blog post: https://modeloop.net/Blog/P2E11-Data-Validation-in-Excel-Drop-Down-Menus-That-Keep-Your-Model-Clean
📺 Watch the video lecture: https://youtu.be/atQfF-APl0g
🎓 Courses: Excel for Financial Modelling | AI in Project Finance Modelling
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ModeLoop is hosted by Samir Asadov, CFA, ranked top 3 financial modeller worldwide (FMWC), with 15 years in M&A and project finance for renewables.