Do users understand this hybrid checkbox/radio control? [duplicate]

Question

I'm wondering about the perennial problem that arises when presenting multiple options, where the user can select none, one, or several options.

Using checkboxes, it's not clear whether a user

• intentionally selected none of the options
• or just ignored the question.

Like so:

^{download bmml source – Wireframes created with Balsamiq Mockups}
See. I don't know whether you don't like any fruit, or whether you just don't want to tell me.

So if I need to know whether the user answered the question, then it makes sense to include a "none of the above" option at the end of the checkbox list. However, there's not a clearly good way to include a "select none" option in a list of checkboxes.

With a small number of options, radio buttons may be a suitable workaround....

^{download bmml source}

...but with a larger number of options, radio buttons quickly become untenable:

^{download bmml source}

So I was quite excited today to stumble across what might be a solution to the problem—a hybrid checkbox/radio control:

^{download bmml source}

When the radio button is selected, the checkboxes become deselected, and when the checkboxes are selected, the radio becomes deselected.

At first glance, this looks like a great solution...but before I start adopting it, I want to check if it may confuse people. Perhaps they view the separate shapes as corresponding with separate questions; or perhaps they don't understand why clicking on some things (but not just any thing) may cause others to become deselected; or perhaps they don't distinguish between checkboxes and radio buttons at all and they're slowed down by wondering why one of the buttons is a different shape from the others.

Has user testing found that this control is commonly understood? Are there particular demographics or psychographics that find this hybrid control problematic?

Answer 1

I can't answer your direct question as to whether or not mixing radios and checkboxes in one list has any conclusive testing data. But I will say it's not something I've seen.

I'd suggest considering some alternatives.

Visually separate the 'none of the above' checkbox from the rest

Select the fruit you like:
[ ] apples
[ ] bananas
[ ] oranges
-----------
[ ] none of the above

Use radio buttons with conditional checkboxes shown when applicable

Default view:

Do you like fruit?
( ) yes
( ) no

If 'yes' is selected:

Do you like fruit?
(•) yes

    Please select your favorite(s):
    [ ] apples
    [ ] bananas
    [ ] oranges

( ) no

Answer 2

• I would like to see checkbox where i can select multiple items (fruits). Everyone loves fruits and they might love more than 1 or 2 fruits. So, I prefer checkbox.
• Radio buttons are used to get a single answer rather than multiple (Like yes/no, close ended questions).