The "Tax Rate" is the ______ used to compute reemployment tax.

The term "Tax Rate" refers specifically to a percentage that is applied to compute reemployment tax. In the context of taxation, a percentage expresses the proportion of tax applied to a specified base, which in this case includes wages or employee earnings subject to reemployment tax. The tax rate is instrumental in determining how much an employer must contribute based on the overall payroll expenses.

Using the correct terminology enhances clarity in understanding how taxes are calculated. While the other terms may relate to taxation, they do not specifically function the same way as a percentage does in this scenario. The "amount" could refer to a total dollar figure that results from applying the rate, while "factor" and "total" are broader terms that don't capture the specific mathematical function of a tax rate in calculating the owed tax. Thus, the percentage is the precise measurement needed for computing reemployment tax direct from the taxable amount.