For which purposes are certain performance metrics of contextual advertising suitable?

There are various systems for evaluation of advertising campaign successfulness, each of them has its own advantages and disadvantages. Let's consider the basic performance metrics of contextual promotion in order to identify the areas where each of them will fit the best.

CTR

It counts the relation between advertising content and amount of clicks it got. This metrics is suitable for determining the success of an advertising platform and finding target audience. But it doesn’t show total income from the campaign, since it doesn’t use an ultimate performance measurement tool.

CPA & CPO

The ratio between the cost of advertising and specified action made (CPA – cost per action) or order (CPO – cost per order). Both models are relatively equal regarding their effectiveness and even use common software for data calculation. The only difference is that CPA doesn’t necessary require product acquisition. For example, if customer requires subscriptions for a news portal, CPA is perfect for results calculation.

ROI & share of ad spend

ROI means the investment gains compare favorably to investment cost, while share of ad spend is the correlation between promotional expenses and total income. Share of ad spend is especially popular in the CIS countries. Both metrics are designed for long-term advertising campaigns and calculation of final results. The disadvantages include complexity regarding the collection of all available data, but modern programs can facilitate this process significantly. Nevertheless, the results will be less objective compared to those received with the help of mentioned above metrics.