What is wrong with this formula?

you're trying to reference a column in a measure, but you're doing it in a row context-dependent way that doesn't work properly in a measure (which evaluates in filter context).

Use a Calculated Column if you need row-by-row evaluation

IncludeDate =

IF(

    NOT ISBLANK('YourTable'[EDC Go-Live]),

    IF('YourTable'[EDC Go-Live] >= 'YourTable'[First Date to Include], 1, 0),

    BLANK()

)

Use a Measure only if aggregating (e.g., MIN, MAX, FIRSTDATE)

IncludeDateMeasure =

VAR EDCDate = SELECTEDVALUE('YourTable'[EDC Go-Live])

VAR FirstDate = SELECTEDVALUE('YourTable'[First Date to Include])

RETURN

IF(

    NOT ISBLANK(EDCDate),

    IF(EDCDate >= FirstDate, 1, 0),

    BLANK()

)

This works only if a single value is in context (e.g., when filtering by row in a visual or drillthrough).