Here is a sample on how to create an if test in DAX. It is really easy 🙂 In the sample below we test the sales per month for 2007 versus the sales per month for 2006. If the sales are higher we print “Higher”. If it was lower we print “Lower”.

DEFINE
    MEASURE 'Internet Sales'[Previous Sales per month] =
        CALCULATE (
            'Internet Sales'[Internet Total Sales],
            SAMEPERIODLASTYEAR ( 'Date'[Date] )
        )
    MEASURE 'Internet Sales'[Sales per month] =
        CALCULATE (
            'Internet Sales'[Internet Total Sales],
            'Date'[Month]
        )
    MEASURE 'Internet Sales'[MyTest] =
        IF (
            'Internet Sales'[Sales per month]
                >= 'Internet Sales'[Previous Sales per month],
            "Higher",
            "Lower"
        )
EVALUATE
FILTER (
    SUMMARIZE (
        'Date',
        'Date'[Month],
        'Date'[Calendar Year],
        "Previous Sales per month", FORMAT (
            'Internet Sales'[Previous Sales per month],
            "Currency"
        ),
        "Sales Sales per month", FORMAT ( 'Internet Sales'[Sales per month], "Currency" ),
        "Change", 'Internet Sales'[MyTest]
    ),
    'Date'[Calendar Year] = 2007
)