Minimum wage is the smallest amount of money per hour that an employer may legally pay a worker. It may be established by law to cover all workers or only those in certain industries. Self-employed persons and employees of small businesses are often not covered by minimum wage laws. Minimum wage laws are intended to raise wages for low-income workers without substantially reducing their job opportunities. Economists, however, do not agree on whether the minimum wage is actually an effective tool. Some economists feel employers do not hire as many low-income workers as they would if no minimum wage existed.