Understand DAX Context in Power BI: CALCULATE, Filter Context & Row Context (Part 2)

Video by: Reid Havens

The single biggest concept separating DAX beginners from confident report builders is context. This interactive guide breaks down how Power BI evaluates every formula you write: what filter context is, how CALCULATE manipulates it, the difference between row context and filter context, how context transition bridges the two, and why iterator functions like SUMX create their own row context. If CALCULATE has ever confused you, start here.

Topics covered:

• The mental model shift: why DAX doesn't think like Excel

• Query context: how rows and columns shape evaluation

• Filter context: slicers, relationships, and implicit filters

• CALCULATE: overriding, replacing, and adding filter arguments

• Row context: calculated columns, iterators, and the current row

• Context transition: what happens when CALCULATE meets row context

• Iterator functions: SUMX, AVERAGEX, and row-by-row evaluation

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(Livestream Replay) Demystifying [DAX] Evaluation Context - with Brian Grant

DESCRIPTION 📄

“DAX Evaluation Context”, just the name alone strikes fear into the heart of even seasoned Power BI developers. The reality however, is that Evaluation Context in DAX isn’t hard to understand, it’s simply hard to describe. In this session Brian Grant will use a technique called "Formula Decomposition" to visually break down a big DAX formula into a chain of smaller, bit-sized sub-formulas; this in turn will create the platform needed for Brian to make the concepts of Evaluation Context both clear to understand and easy to remember.

At the end of the presentation you will both have a clear idea of how to visualize Row and Filter Context, and also understand how the sub-formulas leverage these contexts to produce the answers you see on a Power BI page. Furthermore, the next time you look at a big intimidating DAX formula, you will know how to break it down into bite sized chunks so they can be understand one at a time.

GUEST BIO 👤

Hailing from the East side of beautiful Portland Oregon, Brian is a Senior Business Analytics consultant with local data heroes Skypoint. Having spent his early years deep in the study of acting and screenwriting, he finally graduated Summa Cum Laude with a degree in Economics. His driving belief is that the biggest barrier most people face when learning technology isn't technology at all, but language. Taught the right way, most people can learn most things; helping people learn skills that are "too technical" for them is his greatest joy. He is the author of the Elements of DAX series on YouTube.

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