Doubling budget = 1/4 impressions and clicks

[kevinfishburne]

I've been using AdWords since 12/01/07 with great results and have been very pleased. I noticed that when modifying ads, adding new keywords, etc., that Google gets crazy for about 24 hours and the stats are terrible. After 24 hours they build back up to normal levels. This time I'm stumped, and I don't think it is a coincidence with an external event (competitor's higher bidding, etc.), but rather a problem with AdWords.

I use 27 keywords and one ad group of six ads, all selling different desktop PC models. All link to the same landing page, but jump to a different HTML anchor for each specific model PC. That way they see the specific PC in the ad, but don't have to click anything else to see the other models.

At 11:45 PM on 03/24/08 I doubled my monthly budget from $200 to $400. I examine statistics with one week granularity, and wanted to establish a one-week baseline for budget doubling versus my old $200 budget. If there results were acceptable I'd leave the $400 budget in place and continue to refine other changes on a weekly basis. Below are the results, before and after the budget doubling. Keep in mind, -no- changes were made other than the monthly budget and campaign-wide max CPC. The max CPC was always higher than I've ever actually used for my keywords ($0.90 - $13.33).

February 1 - 29

$200 Monthly Budget
$6.66 Daily Budget
$6.66 Max CPC
Budget Optimizer On

1,478 Clicks (60/day)
1,905,792 Impressions (65,717/day)
0.07% CTR
$0.13 CPC
$190.52 Cost ($6.57/day)

March 1 - 24

$200 Monthly Budget
$6.66 Daily Budget
$6.66 Max CPC
Budget Optimizer On

996 Clicks (42/day)
1,154,607 Impressions (48,109/day)
0.08% CTR
$0.16 CPC
$158.46 Cost ($6.60/day)

March 25 - 26.5 (3:00 PM - 3 Hours)

$400 Monthly Budget
$13.33 Daily Budget
$13.33/$0.90 Max CPC
Budget Optimizer On

19 Clicks (13/day)
27,055 Impressions (18,037/day)
0.07% CTR
$0.15 CPC
$2.87 Cost ($1.91/day)

On 03/14/08 I added keywords 26 and 27, which may explain the differences between stats set 1 and 2. For the last set of stats, the results are based on 1.5 days for today and yesterday. They were taken at 3:00 PM, and I calculated the daily results by counting today as 0.5 days since Google could have been 3 hours behind in reporting. There are two values for max CPC because I first used $13.33, then changed it to the recommended $0.90. Either way no keywords have ever been higher than $0.20 in practice.

I understand that I can manually set my CPC, remove some keywords since there are so many (27), etc. I've read a million forum posts, watched the Black Book DVD, and all that. What I'm wondering is:

1. Why would I get less impressions and clicks after doubling the budget of my already-successful campaign?
2. Should I continue to wait things out to see if it changes?
3. Is this typical of budget changes?
4. What are the odds this is actually the result of insanely-coincidental external factors?

Thanks so much.

Kevin Fishburne, Eight Virtues
www: Eight Virtues PC Sales - Home
e-mail: sales@eightvirtues.com
phone: (770) 853-6271