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KEYWORDS FOR DATASET: Minimum Wage, Unemployment
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ACCOMPANYING DATA PROVIDED BY: Guido Imbens
			       UCLA, Dept. of Economics
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GENERAL EXPLANATION OF THE STUDY
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The accompanying data were used to study the effects of an increase in the 
minimum wage on unemployment. According to conventional economic theory, 
perfectly competitive employers will always cut their work force in 
response to any rise in the minimum wage. In practice, however, 
employer reactions are not so clear-cut: While some studies in the 
seventies confirmed the predictions of theory, earlier studies from the 
sixties, as well as more recent studies conducted in the early nineties, 
concluded that employment was unaffected by increases in the minimum wage.

This study sought to clarify the issue. The New Jersey minimum wage 
increase of April 1, 1992, which raised the minimum wage from $4.25 to 
$5.05, provided a perfect opportunity. Because the fast-food industry 
employs predominantly low-wage workers, because the absence of tips 
simplifies the measurement of wages, and because fast-food restaurants are 
relatively easy to sample, the study chose to assess the effects of the 
minimum wage increase on a random sample of Burger King, Wendys, KFC, and 
Roy Rogers restaurants in New Jersey and eastern Pennsylvania. The 
restaurants were interviewed about one month before, and about eight 
months after, the wage increase went into effect. Information was 
collected at each restaurant about variables such as the number of 
employees, various product prices, and store hours. This data provided 
everything necessary to calculate the impact that the minimum wage 
increase made not only on employment rates, but also on food prices, which
can always be raised to compensate for higher wages. Finally, since 
unemployment is affected by factors other than the minimum wage, the study 
made careful use of controls. The data from the restaurants in Pennsylvania,
as well as data on a number of restaurants in New Jersey that had been 
using the new five dollar minimum wage as a base salary even before the 
official increase went into effect, provided these naturally.

More details from the study may be found in the original article, whose
citation is below. This article is available on the web at JSTOR at 
"www.jstor.org".   

Card, David and Krueger, Alan. "Minimum Wages and Employment: A Case Study
	of the Fast-Food Industry in New Jersey and Pennsylvania." The 
	American Economic Review 84.4 (Sept. 1994) 772-793. 


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BRIEF DESCRIPTION OF THE DATA          
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The final data set contains information on 410 restaurants randomly chosen
from phonebooks in New Jersey and eastern Pennsylvania. For each 
restaurant information is provided on 46 variables; about half pertain 
to the period before the minimum wage increase, and about half concern the
period after.  

After it was chosen from the phonebook, each restaurant was called for a 
telephone survey. To elicit a response restaurants were called back as 
many as nine times, and the researchers obtained 410 completed interviews--
an 87 percent response rate.
  
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HOW TO USE THE DATA FILE
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The data file is comma delimited text. The first row contains the list
of variables and each remaining row contains the corresponding data for
an individual restaurant. Missing data are indicated by a period. 
Explanations for all variable abbreviations are given below. 

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EXPLANATION OF DATA MEASUREMENT ABBREVIATIONS IN THE DATA FILE
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SHEET           sheet number (unique store id)
CHAIN           chain 1=Burger King; 2=KFC; 3=Roy Rogers; 4=Wendys
CO_OWNED        1 if company owned
STATE           1 if NJ; 0 if Pa                      

Dummies for location:

SOUTHJ         1 if in southern NJ
CENTRALJ       1 if in central NJ
NORTHJ         1 if in northern NJ
PA1            1 if in PA, northeast suburbs of Phila
PA2            1 if in PA, Easton etc
SHORE          1 if on NJ shore

First Interview:

NCALLS         number of call-backs*
EMPFT          # full-time employees
EMPPT          # part-time employees
NMGRS          # managers/ass't managers
WAGE_ST        starting wage ($/hr)
INCTIME        months to usual first raise
FIRSTINC       usual amount of first raise ($/hr)
BONUS          1 if cash bounty for new workers
PCTAFF         % employees affected by new minimum
MEALS          free/reduced price code (See below)
OPEN           hour of opening
HRSOPEN        number hrs open per day
PSODA          price of medium soda, including tax
PFRY           price of small fries, including tax
PENTREE        price of entree, including tax
NREGS          number of cash registers in store
NREGS11        number of registers open at 11:00 am

Second Interview:

TYPE2         type 2nd interview 1=phone; 2=personal
STATUS2       status of second interview: see below
DATE2         date of second interview MMDDYY format
NCALLS2       number of call-backs*
EMPFT2        # full-time employees
EMPPT2        # part-time employees
NMGRS2        # managers/ass't managers
WAGE_ST2      starting wage ($/hr)
INCTIME2      months to usual first raise
FIRSTIN2      usual amount of first raise ($/hr)
SPECIAL2      1 if special program for new workers
MEALS2        free/reduced price code (See below)
OPEN2R        hour of opening
HRSOPEN2      number hrs open per day
PSODA2        price of medium soda, including tax
PFRY2         price of small fries, including tax
PENTREE2      price of entree, including tax
NREGS2        number of cash registers in store
NREGS112      number of registers open at 11:00 am

Codes:

Free/reduced Meal Variable:
0 = none
1 = free meals
2 = reduced price meals
3 = both free and reduced price meals


Second Interview Status:

0 = refused second interview (count = 1)
1 = answered 2nd interview (count = 399)
2 = closed for renovations (count = 2)
3 = closed "permanently" (count = 6)
4 = closed for highway construction (count = 1)
5 = closed due to Mall fire (count = 1)


*Note: number of call-backs = 0 if contacted on first call

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STATISTICAL TESTS AND ANALYSES USED IN THE STUDY
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1) t-test for difference of means
2) Basic Linear Regression