Poll: A yes/no question in a web form, which control(s) would you use?

We’re creating a web application that asks a number of questions about pumps (as it happens). Some of these questions are typical yes/no questions. But we need to make sure the user makes a positive choice. We don’t want to impose a choice on them. Which controls would you use?

Here’s the question with the three options we’ve currently got:

Jakob Nielsen at useit.com in his article Checkboxes vs Radio Buttons tells us that radio buttons are used “when there is a list of two or more options that are mutually exclusive and the user must select exactly one choice” and a single checkbox is used “for a single option that the user can turn on or off”. But this case is a little special since we don’t want the user to forget to select something. The nice thing about using the radio buttons or the drop-down is that you have a way of detecting if the user has actually chosen anything yet. On the whole though, the drop-down list is probably the least user-friendly though perhaps the easiest to generate programmatically.

This poll is now closed.