LOD Expressions Don’t Have to Be This Confusing
You’re Not the Only One
“I’ve been staring at this FIXED LOD for 45 minutes. It returns the right number in one view and completely wrong numbers in another. I don’t understand what’s happening.”
“INCLUDE vs FIXED — I’ve read the documentation five times and I still can’t tell when to use which one.”
“My nested LOD worked in dev but broke the moment I added a filter. How does anyone maintain these?”
Why LOD Expressions Are So Tricky
Level of Detail expressions operate at a different granularity than your view. That means the result depends on which dimensions are in your viz, what filters are applied, and in what order. FIXED ignores almost all filters. INCLUDE adds granularity. EXCLUDE removes it. And the interaction between these keywords, your filter shelf, and context filters creates a combinatorial puzzle that even seasoned Tableau developers trip over.
Most AI tools can’t help because they don’t know your data model. They’ll give you a generic FIXED expression template, but they can’t see that your [Region] field is actually coming from a blended data source, or that you’ve got a context filter that changes everything.
How VizWhiz Actually Helps
Drop your .twb or .twbx file and VizWhiz extracts every calculated field, data source, filter, parameter, and relationship in your workbook. Then when you ask “Why isn’t my LOD returning the right values?” — the AI can actually see the answer.
- Sees your exact field names, data types, and how they connect across data sources
- Understands which filters are context vs. dimension vs. data source filters
- Can trace why a FIXED expression behaves differently after adding a filter
- Suggests whether INCLUDE or EXCLUDE is the right approach for your specific scenario