matching up and auto populating

[The Grim Discovery]

	A	B	C
1	Reference	Eligible
2	ABC	Yes
3	123	Yes
4	DEF	No
5	123
6	123
7	GHI

<tbody>
</tbody>

Hiya

Can anyone help me with the following problem.
If a value in Col A is repeated elsewhere in Col A I'd like its corresponding cell in Col B to be automatically populated. In this instance cells B5 & B6 should populate with a 'yes' because of the data in Row 3. Col A could contain an almost infinite range of references - many of which wont duplicate but some will.

Thanks in advance.

 

[AlanY]

try

=IF(COUNTIF(A:A,A2)>1,"Yes","No")

 

[jmacleary]

Hi there. Put this formula in B2 and drag down: =IF(COUNTIF(A:A,A2)>1,"Yes","No")

This will flag all instances where the reference is duplicated, including the first instance.

 

[The Grim Discovery]

Thank J and Alan - appreciate your time and knowledge.