This might seem hypocritical at first since I did create an article explaining that changing ad categories will improve your Adsense CTR. This is true. However, from increasing your CTR, you may in fact be significantly decreasing your CPC which ultimately means you will be losing money from changing ad categories.
The way I came to this conclusion was from looking at what makes a CPC high being competition. Take an example such as the PPC program Ad Dynamo. There are near to no advertisers out there which means there will not be many advertisers bidding for keywords and ad spots. This will relate to a low CPC for publishers of Ad Dynamo.
Take this logic of ‘supply and demand’ and then apply it to Adsense. Although the ad categories that you are blocking have low CTRs (if any clicks at all), you are blocking thousands if not millions of advertisers from bidding for your advertising space from blocking the ad category. Therefore, there will be thousands/millions of advertisers that will not be able to bid for your ad space and raise the CPC. Let’s create an example.
I (metaphorically) have a website about football. Before blocking any ad categories, I had a CTR of 1% and a CPC of £0.40. If I was to get 10,000 impressions, I would make £40.
I then decide to remove the ad categories that are gaining impressions but not producing high earnings output. My CTR rises dramatically to 1.6%. However, my CPC decreases to £0.22. If I was to get 10,000 impressions with there new statistics, you will find I would have only made £35.20: £4.80 less than without blocking ad categories.
The point of this article is that lots of advertisers think the main and only variable they can control in PPC is the click through rate. However, I believe you can change your CPC just as if not easier than the CTR. For example, I have already created an article highlighting 14 ways you can increase your Adsense CPC. Next time you block an ad category, just think about what you might be doing to your CPC: although you are trying to make more money from blocking the category, you may in fact be preventing yourself from making any more money.