Exactly how do you decide that a tax return position is “more likely than not” to be sustained when examined? If “substantial authority” is what you need to support a return position, how do you determine that? What is the value of proposed regulations? What authority are IRS return instructions? Which Court decision is the strongest authority? Will a 2004 private ruling be “substantial authority” for a 2008 return position? OK, so you found the answer, what information do you need to cite it correctly? Will your opinion, when issued, meet the requirements of Circular 230, Section 10.37? When should return positions be disclosed on Form 8275, or Form 8886? Answers to these and 100 more questions about tax research procedures and authority are part of this program.