Measure the time it takes to insert the reference and how much attention is spent productively?
Ctrl-Alt-P- paste a title, wait, Enter to search the web, wait, check the first reference that it is continuously highlighted (meaning the title is correct), maybe check the year, Enter, done.
You see it works fine in 95% of cases, just the search by title or title and authors, so these waiting times and clicks could be eliminated. But the user still would need to do a quality control of the match and if the ref is already in the database to make sure not to add a duplicate. Right?
So the shortest interface would be
1. Ctrl-Alt-P - grab the title from the clipboard, search the database, if it is there, insert the reference and let the user to QC it in the pop-up box.
2. If the title is not in the database, search the web and insert the best match, with say 87% match of the words in the title, and check that they are in the same sequential order. Offer the user a graphical (pie chart) image of the march percent for QC and the list of matches as it is now. Make it visible whether the ref came from the web or from the users database.
3. If all is good, press Enter or click Accept to dismiss the info. Or "Options" to make a manual selection.
This way the waiting is less, the process is even more automated.