For Canada, the Fraser Institute also includes a "Personal Tax Freedom Day Calculator" that estimates a customized Tax Freedom Day based on additional variables such as age of household head, sex of household head, marital status and number of children. However, the Fraser Institute's figures have been disputed. For example, a 2005 study by Osgoode Hall Law Professor Neil Brooks argued the Fraser Institute's Tax Freedom Day analysis includes flawed accounting, including the exclusion of several important forms of income and overstating tax figures, moving the date nearly two months later.