Don't worry, if the FDA 1572 seems confusing, you are not alone. In fact, the FDA updated its Information Sheet Guidance for Sponsors, Clinical Investigators, and IRBs--

Frequently Asked Questions Statement of Investigator (Form FDA 1572)

The document was posted in July 2008, but according to an Applied Clinical Trials Editorial Advisory Board member believes with the myriad of
  activities that clinical operations staff are responsible for some seem to have "missed" this update.

Also, a previous Applied Clinical Trials 

 on the subject could provide more help. 


Online Extras

FDA has updated its guidance documents for 1572s.