Mandatory fields on forms - any studies available?

[jogr]

Have to convince my CEO that it’s a bad idea to have a lot of mandatory input fields in the registration process.

Does anybody know of any studie(s) that shows the negative affect that a lot of mandatory fields will have on the conversion rate.

[Marcia]

Is it registration to be able to submit an order, or to provide leads for information, or for a membership? That can make a difference, although generally studies have shown that the simpler the better.

BTW, here's a classic thread on site conversion with a number of good tips based on people's experience and testing:

[webmasterworld.com...]

[jogr]

The registration is to be able to submit an order.

[DrDoc]

All you really need to capture is:

Address (shipping and billing)
Payment info (generally CC)
Email/Phone (contact info ... and the former for sending promos)

Anything in addition to that is fluff and not mandatory, per se.

[jogr]

Yes, I know that but I have to convince my CEO that more mandatory input fields is a bad idea. Therefore am I looking for a report or studie that clearly shows how the abandon rate increases with more mandatory input fields.

[DrDoc]

This is a good start:
Forms vs. Applications (by Jakob Nielsen) [useit.com]