The Form W-4 is fundamental to the payroll department. It serves as the foundation for the taxation of an employee’s paycheck and is also a required IRS form. Failure to handle the form correctly and completely can open the door to serious problems not only in properly withholding from the employee’s gross wages, but could extend beyond the regulations and affect payroll customer service or employee morale. It can also lead to costly expenditures of time and budget resources to correct non-compliance consequences.