Pay Per Click - optimise or rotate?
Now this may not be the most important factor in running a successful pay per click campaign, however, it has often been of interest to me how best to have your ads served to users from your account. Is it best to optimise or rotate?
Optimise, which is set as the default, favours ads with higher historic CTRs and quality scores. These favoured ads enter the ad auction more often than other ads within the ad group. Then, the system will consider the ad's Quality Score and cost-per-click (CPC) bid before ranking the ad on a given page. Since these higher quality ads enter the auction more often, they will gain more impressions compared to other ads within the ad group, resulting in higher ad served percentages.
Rotated ad serving delivers ads more evenly and will not favour ads with higher CTRs when entering ads into the ad auction. All ads within the Ad Group will enter the auction an equal number of times. All ads within the ad group are likely to gain the same number of impressions, reflected by similar ad served percentages.
When building an account the most important factor is quality score, the optimum number of ads to run per ad group to best drive quality score is 3. If you leave the default setting to optimise these ads then Google’s algorithm will automatically serve the ad with the best CTR and quality score. The strange part of this is that this can happen after 2 or 3 days of the campaign going live, how can the algorithm have fairly tested the quality of all ads enough to favour one over the other.
Setting the ads on rotate is the choice that I would favour on a pay per click campaign. Yes quality score is a very important factor on your account, but the most important is what the user does on your site and whether they convert, ad text is an important part of this. Just because an ad has a better CTR bringing more traffic to the site doesn’t mean that it will necessarily be the best converting ad in the group.
All the ads that you write for your group should be of the same keyword density and quality, the only way to truly test these ads against one another is to rotate then evenly and analyse the results for your pay per click campaign moving forward.
