My questionnaire will look at the response time to each question. So, the "Next" button is really annoying, especially because it is located far away from the answer options. Is it possible to remove the "Next" button, or center the "Next" button on the screen?

How will you move on to the next question without the next button?

Centering the "next" button can surely be done within the survey theme.

Thank you for your quick reply! I mean, can it go on to the next question when the current question is answered?

There are ways to trigger the "next" button via Javascript. Have a look in the forum, you should find ways to do this. But of course, only works with certain question types (e.g. doesn't make sense for multiple answer questions or text questions, as you don't know when someone finished to answer - so basically only single choice questions).

By the way: Measuring the response time isn't very reliable in an online survey. It very much depends also on other factors than just the pure time for the respondent to answer (e.g. slow internet connection, slow server, high load, etc.). If your survey relies heavily on response time and it needs to be very exact, I think you can only do it in an controlled environment.

Yes, I totally agree. Thank you very much for all your advice!

Here's a post about auto-clicking the "Next" button - www.limesurvey.org/forum/design-issues/1...-in-version-3#164666

That is great. Thank you very much!
The script works very well for drop-down and radio questions, but how can I modify the script to make it also work for yes-no questions?

I've just found this link www.limesurvey.org/forum/search?query=ye...dforums=1&ids=115270
It has solved the above problem.