Looking on the internet deeply has found these results:

this is the reason for is the most popular phrase on the web. 

Related Comparison

• this is why or this is the reason why?
• Which counter do i have to go or Is this the counter to?
• this is the main reason for or this is the main reason of?
• owing to or this is owing to?
• this is reference to or it is reference to?
• this is the reason why or this is the reason that?