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Time to get a bit geeky about PPC! This isn’t client related but just an interesting insight into what happens when you read between the lines of Google Adwords. Although Quality Score is the magic number in calculating an ad’s position and CPC, the quality score we see can’t be relied upon to make important judgements. In fact, it could be down right dangerous to even consider it!

Take the following example: An advertiser is running campaigns in two cities (Cityopia and Metroville) targeting their competitor’s brand traffic. All competitors operate in both cities offering effectively the same products, and the keywords used are the same bar any geographical terms. The majority of the Metroville traffic see’s Quality Scores around 6, while Cityopia’s average is 5. While Cityopia’s Quality Score is only slightly lower, Cityopia’s CPC is twice that of Metroville. This suggests that by improving the relevancy of the Cityopia traffic enough to push the average Quality Score up to the same as Metroville, we should see the CPC in Cityopia fall in line with Metroville.

However this isn’t true, because the Quality Score in the graph above is only the VISIBLE quality score, and isn’t the quality score used to calculate the cost per click. It may be indicative of it, but the visible Quality Score shown doesn’t take into account geographical differences and will be an average for all instances of that keyword across the account. Therefore the main competitor terms such as ‘Blue Widget Shop’ and ‘Widgets Emporium’ will have exactly the same visible quality score in both the Metroville and Cityopia campaigns.

In reality, the difference in the graph is due to geo-specific keywords such as ‘Widgets Emporium Metroville’ and ‘Widgets Emporium Cityopia’ which only appear in one city, and make up a much smaller portion of the account. So as only a small portion of terms are responsible for the difference in the graph, and their difference is enough to shift the average of the whole campaign,  it’s likely that the rest of the averaged keywords differ quite significantly as well. The two cities actual Quality Scores could be very different – perhaps closer to being equivalent to a 4 and a 7 and if they were, then the CPC being twice as high for the Cityopia would make a lot more sense.

So in short, optimising your campaign based on the Quality Score you see in your account is dangerous as your actual Quality Scores can be really quite different. A better approach is the time honoured tradition of gut instinct and hard won experience. There’s still a lot that can be drawn from the visible Quality Score metric, but it needs to be treated properly and not substituted for common sense.

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