Understanding eager vs. strict evaluation in DAX
A conditional expression in DAX – like an IF function – can be evaluated in two ways: eager and strict. Understanding the difference between the two evaluation modes can be very useful in finetuning the performance of a measure. The examples in this article cover strict and eager evaluation. The goal is to equip you to make an informed decision in picking the best evaluation mode for a specific data model.
The first example is a simple measure that performs a comparison and then returns one of two different values depending on the outcome of the comparison. Consider the following query: