I am just trying the following method for improving CTR for poor performing keywords across adwords a/c. I basically target ads towards US demographics, but had an entry barrier due to high minimum bids. Hence changed the targeting to Other countires such as Australia, UK, etc. (excluding USA). I saw a dramatic increase in CTR from 0.5% to 21%.
Now advice, if I change the targeting back to USA, will the CTR's for keywords still hold?