Labour theory of value

The Labour Theory of Value is a theory that says the value of something (like a good or service) comes from how much work it took to make it and the effort it took to get it. For example, if you were making a sweater, the labour you put into it would be part of the value. The materials and supplies that you used to make it would be another part of the value. The theory says that if something takes more effort to make, it will be worth more.