Impression Share Anomaly?

AdWords impression share not increasing with bid increase

[JavaCofe]

I might have picked up the wrong understanding of Impression Share along the way but I thought the higher you bid the greater share of voice you would get. So I would expect the Impression Share of a campaign to move outside the daily churn when I increase bids.....?

For the 19days preceding the trial CPC was about 1.66; Avg Posn 4.3 and Impr. Share between 28-33%

3 trial days CPC was circa £5 avg posn 1.7 with avg position 28-31%


following the CPC increase the share dropped to 13-16% though there were quite a few campaign structure changes though nothing except bids in the first 22 days.

[JavaCofe]

*3 trial days CPC was circa £5 avg posn 1.7 with impression share 28-31%

[eWhisper]

Did you raise your daily budget or hit your budget each day? If you were already hitting your budget, raising your CPCs would lower your IS as you will get less clicks each day.

[JavaCofe]

nope, I always set daily PPC campaign budgets about 50% in excess of what I expect to spend.

[RhinoFish]

"Impression share is a metric that represents the percentage of impressions your ad received out of the total available impressions in the market you're targeting."

your higher bids may have caused some keywords to become active, growing your "market".

similar effect to raising your bids can lower your average position...

see that explained here:
[adwords.blogspot.com...]

[TheresaZ]

My personal experience suggests there are IS "thresholds" (unadvertised and unconfirmed). That is, a bid increase of 10 cents might not kick one keyword up into the next "tier" in one case but a bid of 2 cents might do it in another case.

Also, as far as I know, the system seems more inclined to serve additional traffic mostly when performance metrics--quality scores and CTRs--are good and have been good for a period of time. (IN other words, you can't just bid your way into more traffic--the quality of your campaign is a big factor.)