Ok, if you are adding calculated column. Your formula works. You'll then use SUM() on the column as measure. Note that I added Custom column to turn even rows to "ICSEA Eligible" as all your record were for "ICSEA Not Eligible".
However, I'd advise against adding this type of calculated column (it does not reduce filter context, and is a bit pointless). Calculated columns should mainly reside in Dimension table.
To count using condition in DAX, there are several ways. In this case, since all data is based on single table, you can simply use COUNTROWS() with filter.
ex:
Measure = COUNTROWS(Filter(Table1,[ICSEA Eligible]="ICSEA Eligible")