Which one keyword to show

[peony]

let's say I have 2 keywords ,"widgets" and "blue blue widgets", in the same adgroup. how adwords decide which keyword to trigger ad?

[jtara]

The one that is more specific.

[robertskelton]

Your keywords are treated as competitors to each other. All qualifying keywords for a search result are judged by factors like CTR and maximum bid and lots of lesser stuff. Whichever of your keywords that ranks highest based on those factors will the one used.

For example:

"widgets"
CTR 1%
max cpc $1.00

"blue blue widgets"
CTR 5%
max cpc $50.00

the latter will win

Rob.

[resham5]

It would also depend on the search query.
If the search query is red widgets OR blue widgets, the "widgets" keyword will trigger your ad but if someone looks for buy blue blue widgets, the keyword "blue blue widgets" will trigger the ad.