Dax FILTER error: "The expression refers to multiple columns"

[Kimber]

I have a table that logs student offenses. It contains data such as Student ID, Date, Offense Type and Suspension Type. I'm trying to write a simple dax filter so I can plot the number of expulsions per year on a line chart. But I'm getting this error and don't understand why:

Can someone help me with this please?

[HamedM1125]

@Kimber Please share sample data!

[Angith_Nair · Accepted solution]

Hi @Kimber 

Use this DAX:

Expulsions Per Year = 
    CALCULATE(
        COUNTROWS('Student Offenses'),
        'Student Offenses'[Suspension Type] = "Expulsion"
    )