Before revision:  To find out how developers and their productivity were affected, we distributed two surveys (with  3,634 responses )---weeks apart to understand the presence and prevalence of the benefits, challenges, and opportunities to improve this special circumstance of remote work.
After revision:  To find out how developers and their productivity were affected, we distributed two surveys (with 3,634 responses that answered all required questions) -- weeks apart to understand the presence and prevalence of the benefits, challenges, and opportunities to improve this special circumstance of remote work.