In you case, where there is one conversion then the numbers for conversions and converted clicks will be the same. But imagine you have another conversion for downloading a pdf which explains your company policy. Then a single visitor might download the pdf, and then decides to complete the application.
That would be one converted click and two conversions. Many sites do indeed have multiple conversions that they track. Imagine two visitors arrive at the site via different keywords - one converts 5 times on the page and the other just once. If we were to count all conversions then it would look as if one keyword were five times as effective as the other - which is misleading.
The other point to bear in mind is the cost per conversion. If the costs for conversion are worked out for each of the above - assuming they each paid $1 for the click then the visitor with a single conversion would be reported as $1 per conversion - but how would we report the other - who converted five times? $1 per conversion or 20¢?
Google actually calculates it as $1 - as a cost per converted click, as this does seem to be the most useful in terms of evaluating campaign performance.
Sign up for AdWords!
