The following array formula placed - initially - in the cell with the red border works:

{=INDEX(Table13[Y/N],MATCH($E5,IF(Table13[ID]=G$3,Table13[A]),0))}

My question is, given that the table will be large, with upto1500 of these cells that need to be conditionally formatted, is this array formula the most efficient method? This is part of a VBA solution. The columns with the conditional formatting will be interleaved into an existing, large table - using VBA.

In summary my question is: given that the conditional formatting will be applied to a very large table, and each 'Y/N' value depends on both the corresponding 'A' and 'ID' values, what is the most efficient method for applying conditional formatting?

All suggestions greatly appreciated.