Until About 10 Years Ago, Most Studies in Labor Economics

question 21

Essay

Until about 10 years ago, most studies in labor economics found a small but significant negative relationship between minimum wages and employment for teenagers. Two labor economists challenged this perceived wisdom with a publication in 1992 by comparing employment changes of fast-food restaurants in Texas, before and after a federal minimum wage increase.
(a)Explain how you would obtain external validity in this field of study.
(b)List the various threats to external validity and suggest how to address them in this case.

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Definitions:

Cornea

The clear, transparent front covering of the eye that allows light to enter and contributes to the eye's focusing power.

Protective Coating

A layer of material applied to objects or surfaces to guard against damage or corrosion.

Fovea

A small depression in the retina of the eye where visual acuity is highest, containing a high concentration of cones for daytime vision.

Sclera

The white outer layer of the eyeball, providing protection and form.