ROI of different usability methods

Hi - I'm looking for data on these topics:

1) Selecting usability methods with respect to ROI. (Which methods result in the highest ROI?)
2) What kind of usability services are most demanded by customers?

Please point me to related reports or information from credible sources.

Regards
Devika



**************** CAUTION - Disclaimer *****************
This e-mail contains PRIVILEGED AND CONFIDENTIAL INFORMATION intended solely for the use of the addressee(s). If you are not the intended recipient, please notify the sender by e-mail and delete the original message. Further, you are not to copy, disclose, or distribute this e-mail or its contents to any other person and any such actions are unlawful. This e-mail may contain viruses. Infosys has taken every reasonable precaution to minimize this risk, but is not liable for any damage you may sustain as a result of any virus in this e-mail. You should carry out your own virus checks before opening the e-mail or attachment. Infosys reserves the right to monitor and review the content of all messages sent to or from this e-mail address. Messages sent to or from this e-mail address may be stored on the Infosys e-mail system.
***INFOSYS******** End of Disclaimer ********INFOSYS***

    --------------------------------------------------------------
        Tip of the Day: Email mailto:[email protected]
               with any comments, questions or problems
     CHI-WEB: www.sigchi.org/web POSTINGS: mailto:[email protected]
              MODERATORS: mailto:[email protected]
       SUBSCRIPTION CHANGES & FAQ:  www.sigchi.org/web/faq.html
    --------------------------------------------------------------