What are the key performance indicators (KPIs) used in CPA marketing?

In CPA (cost-per-action) marketing, there are several key performance indicators (KPIs) that can be used to measure the success of a campaign. Here are a few common KPIs:

1. **Conversion Rate:** Conversion rate is the percentage of users who take the desired action (e.g. filling out a form, making a purchase, or downloading an app) after clicking on an ad. A high conversion rate indicates that the ad is resonating with the target audience and is driving valuable actions.
2. **Cost per Conversion:** Cost per conversion is the amount of money an advertiser pays for each conversion. This KPI is calculated by dividing the total cost of the campaign by the number of conversions it generates. A low cost per conversion indicates that the campaign is efficient and effective at driving conversions.
3. **Return on Investment (ROI):** ROI is a measure of the profit generated by a campaign, calculated by dividing the revenue generated by the cost of the campaign. A high ROI indicates that the campaign is generating a good return on the advertiser's investment.
4. **Click-Through Rate (CTR):** CTR is the percentage of users who click on an ad after seeing it. A high CTR indicates that the ad is relevant and engaging to the target audience.
5. **Bounce Rate:** Bounce rate is the percentage of users who leave a website after viewing only one page. A low bounce rate indicates that users are finding the website or landing page relevant and engaging.
6. **Time on Site:** Time on site is the amount of time users spend on a website or landing page. A long time on site indicates that users are finding the content valuable and engaging.

It's important to note that the KPIs that are most relevant for a CPA campaign will depend on the specifics of the campaign and the goals of the advertiser. It's a good idea to choose a few key KPIs to track and use this data to optimize the campaign and improve the ROI.