Measuring Labor Input
Dale Jorgenson, Mun Ho, Jon Samuels
Harvard University
World KLEMS Conference, Harvard University
August 19, 2010
Topics
- Measurement Issues and Methodology
- Data and Implementation
- Results
- Contribution of labor input to productivity revival
- Criticisms of this method
Information Technology and the American Growth ResurgenceJorgenson, Ho and Stiroh (2005); Chapter 6
New Data on U.S. Productivity Growth by IndustryJorgenson, Ho and Samuels (2010)
Issues in Measuring Labor Input
- Number of workers, or Hours worked, are not suitable units of measure for heterogenous labor
- Wide range of market wages indicate wide range of productivities
- A wage-weighted index have been growing faster than simple sum of hours, productivity residual using hours will overstate the growth of TFP. -Need tractable method of handling this great heterogeneity
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Methodology for a tractable measure of labor input
-Cross classify workers in each industry by demographic characteristics * In Jorgenson, Gollop & Fraumeni (1987): sex, class, age, education, occupation * Now: sex, class, age, education
-Define industry labor input as a Tornqvist index of the demographic components
Gender 2 Male; FemaleClass 2 Employees; Self-employed and unpaidAge 7 16-17; 18-24; 25-34; 35-44; 45-54; 55-64; 65+Education 6 0-8 years grade school
grade 9-12 no diplomaHigh School graduatesome College no Bachelors degreeBachelors degreemore than BA degree
Classification of demographic groups for each industry
2x2x7x6 = 168
Index of labor input for industry j, Ljt as Tornqvist index of components
, , ,
ln lnjt scaejt scaejts c a e
L v L
Lscaej scaej
scaej Lscaej scaej
scae
P Lv
P L
1, 12 [ ]ljt ljt lj tv v v
, 1
ln ln jtjt
j t
LL
L
scae: sex, class, age, education j: industry j or aggregate economy
Index Ljt, cont. Constant Quality Index
scaejt scae scaejtL Q H
Assume labor input is proportional to hours worked:
Qscae is the quality of hours of group scae, fixed for all t.Thus input index becomes:
, , , , , ,
ln ln lnjt scaejt scaejt scaejt scaejts c a e s c a e
L v L v H
, , ,jt scaejt
s c a e
H H Compared to simple hours:
Index Ljt, cont.
L Lt scaej scaej jt jt
scae
value P H P L
Price of industry labor input is simply value/Lj
after choosing a normalization like:
Quality of industry labor input is labor input index divided by hours worked:
jt
jtLjt H
LQ j scaej
scae
H H
,2000 ,2000 20001.0;Lj jP L value
Decomposing the labor input index
Partial indices of labor input. E.g. first-order index by age
ln ln ln( )aa a a saec
a a s e c
L v H v H
How much of the quality change is due to changes ..in educational attainment? ..in the aging of the labor force? …
Contribution of age to labor quality
ln ln lna aQ L H
Data
Need number of workers, hours and compensation to fill matrices of dimension (2sex, 2 class, 7age, 6educ, 70indus).
Total of 11760 cells.
Household survey data (hours/week, weeks/year, wages/year, demographics, industry) Census of Population. - every 10 years - 1% percent sample (1 million workers) Current Population Survey, Annual Supplement (ASEC) - every year, 1964+ - about 100,000 households
Establishment survey data Bureau of Economic Analysis tabulations of total employment, total compensation, wages for 72 industries; annual hours for 18 industries
Implementation
-Begin with Census microdata (1% sample, ~1 mil. workers) to populate EMP, HOURS, COMP matrices for benchmark years
-From CPS annual microdata, construct marginal matrices: EMP, HOURS, COMP matrices of lower dimension (e.g. indus x edu, sex x age x edu, …)
-Interpolate between benchmark years using these annual marginal matrices
-Scale to industry totals in the National Accounts
Data Issues
-Change from SIC to NAICS classification
(CPS 2003+ and Census 2000 uses NAICS)
-Change in education classification in 1992
-Small sample size in CPS (use fewer industries)
-Household data is “top-coded” for wages-Workers in multiple jobs (multiple industries)-Estimating wages for self employed-No data on fringe (non-wage) benefits by person
Table 6.8: Labor Characteristics by Industry, year 2005.
Compen-sation
($/hour)Hours: % aged 16-35
Hours: % females
Females: % college educated
Males: % college
educatedIT Producing
Computer & elec prod. 48.6 27.8 30.4 50.1 66.2Telecom equip 49.7 24.6 30.4 36.5 57.8Electronic components 49.8 26.6 34.0 30.5 56.6Software publishing 40.3 41.1 38.1 72.4 78.4Information, data proc. 43.6 41.9 40.2 53.1 65.6Computer sys. design 48.9 36.8 27.2 65.9 71.2
IT UsingWholesale trade 35.7 26.6 25.8 26.1 28.9Banks, credit interm. 40.0 29.9 61.8 24.8 61.8
Non-ITConstruction 26.3 30.8 8.3 19.2 10.3Hospitals 30.2 23.4 75.3 39.3 49.2
72-industry median 34.7 24.3 33.1 27.7 28.9
December 23, 2000 issue
Labor Contributions to Aggregate Growth
Criticisms of this methodology
- Equation of wages with marginal product is not valid with non-competitive markets and discrimination
- Small sample sizes for many industries give poor estimates of cell averages
- Education is not directly productive and merely a “signal”
- Intensity of work effort is not recognized
Summary
- Simple sum of hours understate labor contribution, overstate TFP growth
- Our labor input index – an aggregate over hours by demographic groups, weighted by wages – is a tractable measure with the use of U.S. Census microdata.
- The growth of labor quality was about 0.4% per year, or, ¼ of the labor contribution to GDP growth is due to labor quality and ¾ due to hours growth.