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Economic Assumptions. Marginal Decisions , Rational Behavior , & Incentives. Economists must make assumptions to analyze/solve problems Why? => Social sciences are not exact Most analysis will “ hold other factors constant ”
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Economic Assumptions Marginal Decisions, Rational Behavior, & Incentives
Economists must make assumptions to analyze/solve problems Why? => Social sciences are not exact Most analysis will “hold other factors constant” Ceteris paribus: Latin for “all other things being equal” Example: If Gov’t ↓ income taxes => consumers income ↑ => spending ↑ The Role of Assumptions • The Reality is that many other factors could offset tax cut: • ↑gas prices, ↑ job loss, ↑ interest rates, etc….
The art in economic analysis is which assumptions to make… wrong assumptions =>poor Gov’t policy => poor outcomes Many economic policies have “unintended consequences” Economist Scientist Assumptions & Gov’t Policy
Important Economic Assumptions: • People make decisions based at the margin • “at the next unit” • People make rational decisions • People respond to incentives
Marginal Decision Making • Decisions are rarely “all or nothing” • Most decisions are made at the Margin • margin = next unit (consumed or produced) • Marginal Benefit (MB) vs.Marginal Cost (MC) • Value of next unit consumedCost of next unit produced
Marginal Analysis • Examples: • Step #1: You decide to study => • Step #2: The Marginal decision = how long to study? • Step #1: You decide to buy popcorn => • Step #2:Marginaldecision = what size to buy? • In economics, when the MB ≥ MC then “do more of it” • Stop when MB = MC
Example: Marginal Analysis Would you pick up $5.00 dollars from the school hallway floor? 500 pennies
Selling Airline Tickets Diamonds vs. Water Lesson: A consumer’s willingness to pay for any good is based on the marginal benefit of an extra unit(i.e. the last unit sold)
Rational Expectations Theory Economic theory stating people make choices based on their rational outlook, available information, &past experiences. This theory is the basis of classical macroeconomics Are human’s really rational?
Rational Decision Making Economics assumes people make rational (logical) decisions • That is, where MB ≥ MC Is this rational? 11 min. Rational Behavior Video: https://www.youtube.com/watch?v=DWh3Y5OyN34 Start at 1:30 in
Incentives Matter! Examples: • Taxes encourage less activity • Subsidiesencourage more activity Government policies alter the behavior of consumers & producers by providing an incentive or disincentive
How would Gov’t ↑ taxeson gasoline $3.00 per gallon change the behavior of both consumersandproducers? PRODUCERS CONSUMERS