COUNTIF in DAX Language
A COUNTIF is sorely missed in DAX.
(The workaround with CALCULATE and FILTER is too cumbersome and complex for most users)
Kenneth Barber commented
One of the beauties of DAX over Excel is that filtration (the "IF" or "IFS" step) is separated from the aggregation step (count, sum, average, minimum, etc.). Instead of introducing a new "IF" or "IFS" function for each type of aggregation (SUMIFS, MINIFS, etc.), you filter your data with FILTER and you use your normal aggregation function on that filtered table.
In DAX, the equivalent of COUNTIF would be this:
COUNTROWS(FILTER('Table',<condition goes here>))
What is the workaround with CALCULATE and FILTER that you had in mind?
You can use COUNTX instead. Btw, CALCULATE and FILTER are most-learn functions in POWER BI, do encourage the users to learn them.