• A useful way to represent the data in a production possibilities schedule is by means of a graph called a production possibilities model 
• oppurtunity cost - the value of the next - best forgone alternative 
• ppf - a graph that shows the possible combinations of two different goods or services that can be produced with fixed resources and tchnology 
• the ppf shows the production combinations that are both attainable and efficient 
• constant oppurtunity cost - a characteristic of production such that the oppurtunity of one good or service, In terms of another, is constant at every level of production of one good or service, In terms of another is constant at every level of production 
• efficient allocation of resources - allocation of resources in such a way that is possible to increase the production ofone good only by decreasing the production of another 
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