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Long Run Costs

  • Short Run - At least one input is fixed. If they don't mention then assume capital (machinery/factory) is fixed.
  • Long Run - All inputs are variable (firms can get more labor and capital). Technological level is fixed.
  • Very Long Run - all inputs are variable and technological improvements can occur.
Image illustrating Long Run Costs


  • Economies of Scale - When average total cost (ATC) decreases. This is a good thing! In the graph above, this occurs from an output of ________ to ________. Example: When Walmart buys can of Pepsi from its suppliers in bulk they get good deals (low cost per can).
  • Diseconomies of Scale - When ATC increases. This is a bad thing! In the graph above, this occurs from an output of ________to ________. Example: If Walmart buys too many supplies (like cans of Pepsi) they might need to buy more storage space or need more workers which can lead to inefficiency and higher costs.
  • Minimum Efficiency Scale - the lowest point of the Long Run ATC curve. In the graph above, this is at an output of ________.
  • Factor Costs - these are input costs (like wages) needed to produce the product. If factor costs decrease, the entire short run and long run cost curves would shift ________


Returns to Scale

  • Increasing Returns to Scale - when inputs are doubled and output more than doubles. In the graph above, this occurs from an output of ________to ________.
  • Decreasing Returns to Scale - when inputs are doubled and output less than doubles. In the graph above, this occurs from an output of ________to ________.
  • Constant Return to Scale - when inputs are doubled and output exactly doubles. In the graph above, this occurs at an output of ________.




Practice: Long Run Costs

In the portion of the long run average total cost that is negatively sloped the firm is experiencing:

Choose an answer

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