Mark input in forms as required even if all input is mandatory?

Question

I looked up many questions and answers here regarding labeling mandatory input fields. The de facto standard is an asterisk * to mark input as required. Also the common approach is to mark the required input as such.

My questions are:

• If all input in a form is required (or only 1-2 fields are optional[1]) - does it still make sense sense to mark all of them as required?
• Is a caption like '* = mandatory input' still needed then or do people know what the asterisk means (balance b/w helpful information and added visual noise by the caption)?

[1] Just highlight the optional ones as such?

Answer 1

If no fields are optional, it would make more sense to have a message on the page saying all fields are mandatory.

If a few are optional, it would make sense to mark them as optional. I would use something different than an asterisk for this. The word "optional" in italics next to the form element is typical.

To be safe, you should still include a message somewhere explaining that * denotes a mandatory field. While it's a pretty common usage, it's not universal.

Answer 2

In general, people that have never seen the added "* = required" wont know it. Try it on your grandmother/mother/father/grandfather. They won't know it if they haven't seen it. The same goes for input fields, if somebody does not know that sometimes fields are required, or vice versa does not know that some are -not- needed, then that users does not know what to do. (this is extreme) I would either add "All fields are required" above or give in line validation (if web: jquery validation) This will aid those that do not understand most forms.