Ekonometrika fani bilan tanishuv

experiments
(1 we’ll discuss this property in more detail later on)

A Note on Randomized Experiments

(cont’d)

16

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  example (returns to education): If a person is chosen from the population and given another year of education, by how much will his/her wage increase?
  
  • 
    randomized experiment:
    
    • 
      Choose a group of people (children).
      
    • 
      Randomly assign a level of education to each person.
      
    • 
      After all of them have finished their schooling and got employed, measure their wages and use statistical methods.
      
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  would you let your child participate in such an experiment?
  
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  is it ethical to force people to participate?
  
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  it’s fairly easy to collect non-experimental data on wages and
  education; however, ceteris paribus doesn’t work here
  
  • 
    education vs. working experience (easy to fix – collect data for exp.)
    
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    education vs. ability (difficult to fix – ability largely unobservable)
    
  • 
    again, we’ll cover this in more detail later on
    

A Note on Randomized Experiments

(cont’d)

17

• 
  example (class sizes): does a kindergarten class size determine a
  pupil’s performance in early years of study (and perhaps afterwards)?
  
  • 
    randomized experiment:
    
    • 
      Tennessee STAR programme (Student/Teacher Achievement Ratio), 1985–1989
      
    • 
      kindergarten pupils randomly assigned to three different class modes:
      

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  13–17 students, 1 teacher (small)
  
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  22–26 students, 1 teacher (regular)
  
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  22–26 students, 1 teacher + 1 teacher’s aide (regular + aide)
  
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  students’ performance tested throughout the following years (SAT)