why can't I use string in IF statement?

[Nietzsche]

I have the following measure

LastReviewDate =

    if(isblank(max(FactPerformanceRating[ReviewDate])),

        "No Review Yet",

        max(FactPerformanceRating[ReviewDate])

    )

ReviewDate is all date format.

When use this DAX, the card vis just show up as #,0.00, and it is not possible to format this measure as date.

how can I change my DAX so that I can use string text inside the IF statement?

source, from DataCamp course case study: HR analystics in Power BI > 9.2 Analysing demographics

[Nietzsche]

oh yes you are night. 

The instruction did ask us to format it, but not in the code, but in the ribbon.

[DataNinja777 · Accepted solution]

Hi @Nietzsche 

I think card visual only takes the output of the same data type.  So for example, in your original formula, the data type can be either date format or string format.  

If you tweak your formula like below, it will produce your required output.  

I also attach the pbix file for your reference.  

Best regards,