Read The Cell Offset 3 To The Right, And Then Set To Either YYYYMMDD Or YYYY Depenig On The Value In The Cell

    For Each C In Sheets("data").Range("A2", Range("A2").End(xlDown))  
           With C
           If IsDate(.Value) Then
               .Offset(0, 3).Value = Format(.Value, "yyyymmdd")
           Else
               .Offset(0, 3).Value = Right(.text, 4)
           End If
       End With
    Next C 

which is supposed to read the cell offset 3 to the right, and then set to either YYYYMMDD or YYYY depenig on the value in the cell. I'm not sure how to specify the first part of this line - .Offset(0, 3).Value = Format(.Value, "yyyymmdd") - it keeps reading the cell in column A, rather than the offset cel.