Which factor is NOT used to determine the tax home of a taxpayer with multiple employment locations?

The determination of a taxpayer's tax home, particularly for those who have multiple employment locations, involves several factors that indicate where their primary work-related activities take place. The total time ordinarily spent in performing duties in each area, the degree of business activity, and the amount of income earned are all relevant considerations since they help establish where the taxpayer has a closer connection and more substantial business presence.

Focusing on the factor regarding the total number of nights spent in each area, while this might seem relevant at a glance, it is not typically a primary determinant of tax home. The IRS looks more at the nature of the employment and the regularity and location of job duties rather than merely counting nights in various locations. Thus, the total nights spent does not necessarily reflect the taxpayer's primary place of business or where they should be claiming their tax home, making it the least relevant factor in this context.