Question - Regardless of whether you are an employee or a sole proprietor, you'll have to prove your entitlement to a deduction before the IRS lets you have it. What kind of substantiation does a taxpayer have to provide to justify a deduction? Does it depend on the type of deduction involved? What's the difference between a refundable and a nonrefundable credit? What types of credits are refundable? Does this seem like good or fair tax policy? Why or why not?