Final answer:
The most appropriate measure of website effectiveness would be the conversion rate.
Step-by-step explanation:
When selecting a measure of website effectiveness to compare two sites, the most appropriate measure would be the conversion rate. The conversion rate measures the percentage of visitors who take a desired action, such as making a purchase or filling out a form.
The click-through rate measures the percentage of visitors who click on a specific link or ad, but it does not necessarily indicate whether those visitors are converting into customers.
The bounce rate measures the percentage of visitors who leave a website without interacting with it further, which may not accurately reflect website effectiveness.
The engagement rate measures how actively visitors interact with a website, but it may not provide a clear indication of the desired action or conversion.