Two Applied Papers on Measurement Error in Wages Downward nominal wage flexibility– real or...
-
Upload
natasha-strawder -
Category
Documents
-
view
214 -
download
0
Transcript of Two Applied Papers on Measurement Error in Wages Downward nominal wage flexibility– real or...
Two Applied Papers on Measurement Error in Wages
• Downward nominal wage flexibility– real or measurement error?
• Impact of Non-Classical Measurement Error on Measures of Inequality and Mobility
Downward nominal wage flexibility– real or
measurement error?
Peter Gottschalk
Question and Relevance
• How flexible are nominal wages in the US?– Nominal versus real wage
• Relevance– Possible explanation for lower
unemployment in US– Claim in literature
• US -- flexible labor market • Other OECD countries--institutional constraints
Implications of flexibility
– Zero nominal change plays no special role– Negative nominal changes result when
negative shocks are greater than inflation
Figure 1Kernel Smoothed Distribution of Percentage Changes
in Reported WagesMales
-0.1 -0.05 0 0.05 0.1 0.15 0.2 0.25
Summary of Studies
• Summary of studies– PSID studies
• Substantial spike at zero– 7-10%• Substantial nominal decline– 15-20%
– Firm specific studies• Negligible nominal decline – 0-2%
• Acknowledge role of measurement error– Issue-- How to separate signal from noise– Requires identifying assumption
Identification
• Use weaker identifying assumptions– No functional form assumption on measurement
error
• Use well developed techniques from Bai and Perron (1998) to find wage changes– Originally developed to find structural breaks in
macro data
Identifying Assumption
• Nominal wages adjust at discrete break points– Work for same employer from t=1…T
– Wages adjust at T1 …. Tm
• yt = β1+ut t=1...T1
• = β2+ut t=T1+1..... T2
• = βm+1+ut t=Tm+1..... T
– No assumption on number of breaks (i.e. Tm >=0)– Weak restriction on frequency of break
• Assume wages do not adjust continuously
– No assumption on size of wage change
Algorithm from Bai and Perron
1. For each job history, calculate SSR for each possible break
2. Find the break with min SSR
3. Test if break is statistically significant
4. If so, repeat for each sub-period
5. Continue until no further significant breaks
Data--Survey of Income and Program Participation (SIPP)
• 1986-93 Panels– Each is 24-40 months long– Monthly data collected every four months– Detailed questions on
• Employer• Wages
Empirical Specification
• Sample– Hourly workers– Males and females while not in school– 18 to 55
• Within firm wage changes– Includes changes to new jobs or assignments– Includes transitions between full and part-time
Probability of Yearly Decline or Increasein Reported and Adjusted Wages
Reported Adjusted Reported Adjusted
Decline 0.157 0.051 0.136 0.043Constant 0.251 0.537 0.228 0.492Increase 0.591 0.412 0.636 0.465
1.000 1.000 1.000 1.000
FemalesMales
Table 4
Table 6Distribution of Changes in Reported
and Adjusted Wages Between Interviews
Reported Adjusted Reported Adjusted
Decline 0.200 0.020 0.180 0.015Constant 0.409 0.858 0.431 0.849Increase 0.391 0.123 0.400 0.136
1.000 1.000 1.000 1.000
Males Females
Figure 2-- Baseline Hazard of Change in Reported Wage
0 5 10 15 20 25 30 35 40duration
hazard
M ale
Female
Figure 3 -- Baseline Hazard of Change in Adjusted Nominal Wage
0 4 8 12 16 20 24 28 32 36 40
duration
hazard
M ale
Female
Conclusions
• Offer new way to correct for measurement error based on weak identifying assumption– wages change at discrete break points
• Reconciles firm studies with PSID studies– Nominal wage declines rare– Tend to occur around 12 month
Impact of Non-Classical Measurement Error on Measures
of Inequality and Mobility
Peter Gottschalk and Minh Huynh
Motivation
• Common presumptions:– Inequality is overstated due to measurement error
• Some cross-sectional variation reflects measurement error
– Mobility overstated due to measurement error• Some cross-sectional variation reflects measurement
error
Motivation
• Measures of inequality and mobility – Often based on self-reported earnings – Reflect joint distribution of
• earnings • measurement error
• Measurement error in – Earnings– Lagged earnings
Motivation
• Classical measurement error– Independent measurement error– Impliciations
• Inequality overstated• Mobility overstated
• Non-classical measurement error– Key properties
• Mean reversion in earnings and lagged earnings• Correlated measurement errors
– Implications• Can’t sign bias• But can derive impact
Overview
• Review of literature
• Analytical framework
• Empirical application
• Conclusions
Theoretical Literature
Theoretical Literature
• Classical measurement error in bivariate regression– Measurement error in x (lagged ln earnings) leads to
• Attenuation bias
• Under-estimate of correlation in earnings
• Over-estimate mobility
– Measurement error in y (ln earnings)• No effect on elasticity
Theoretical Literature
• Bound, Brown and Mathiowitz (2001)– Non-classical measurement error
• impact of mean reversion• Impact in standard regression (not mobility)• Measurement error in y or x but not both
– Findings– mean reversion in measurement error• in x offsets attenuation bias• in y introduces attenuation bias
Theoretical Literature
• Bound, Brown and Mathiowitz (2001) con’t– Not applicable to our problem
• y and x potentially suffer from same source of measurement error
• Measurement errors potentially correlated– with each other – with
Empirical Literature
• Validation studies– Compare
• Reported wages
• Wages from admistrative records or firm’s payroll data
– Findings-- Measurement error• Large
– Var(error)/var(payroll)=.30
• Mean reverting
• Positively correlated across time
Data
• Detailed Earnings Records (DER)– Yearly earnings from tax records (W2 forms)– More complete than FICA tax records
• Social Security maximum
• Uncovered sectors
• SIPP – Exclude self-employment to match W2– 1996 panel– Aggregate to yearly earnings
• 12 months of valid earnings (including zeros)
Data
• SIPP– Top-codes yearly earnings >$150,00
• Replaces by demographic specific mean earnings• We impose same top-coding on DER
– Imputes earnings• 31 percent of yearly earnings have at least one month
imputed• Introduces other source of error that can be avoided• Show results for all and non-imputed
Data
• Matched on basis of Social Security number– Match rate .77
• Analysis Sample– Males 25-62– Not attending school– Valid earnings in t and t-1
Role of Linearity
• Mobility is measured as– Linear correlation– Elasticity from linear projection
• Decomposition is based on linear decomposition– Mean reversion--
• Linear projection of errors on y or x
– Correlated errors
• Are these relationships linear?
Conclusion
• Analytics– Common assumption that measurement error
leads to overestimates of inequality and mobility• Based on classical measurement error assumption• Assumption is wrong
– Impact of measurement error depends on • Mean reversion• Correlation in measurement error
Conclusions
• Empirical Findings– Measurement error in earnings in SIPP,
PSID and CPS is• large• far from classical
– Leads to• under estimate of inequality• little impact on correlation and elasticity
– Large but offsetting bias