Understanding Earnings Dynamics: Identifying and Estimating the Changing Roles of Unobserved Ability, Permanent and Transitory Shocks

Lance Lochner, Youngki Shin

NBER Working Paper No. 20068
Issued in April 2014
NBER Program(s):   ED   LS

We consider a general framework to study the evolution of wage and earnings residuals that incorporates features highlighted by two influential but distinct literatures in economics: (i) unobserved skills with changing non-linear pricing functions and (ii) idiosyncratic shocks with both permanent and transitory components.

We first provide nonparametric identification conditions for the distribution of unobserved skills, all unobserved skill pricing functions, and (nearly) all distributions for both permanent and MA(q) transitory shocks. We then discuss identification and estimation using a moment-based approach, restricting unobserved skill pricing functions to be polynomials. Using data on log earnings for men ages 30-59 in the PSID, we estimate the evolution of unobserved skill pricing functions and the distributions of unobserved skills, transitory, and permanent shocks from 1970 to 2008. We highlight five main findings: (i) The returns to unobserved skill rose over the 1970s and early 1980s, fell over the late 1980s and early 1990s, and then remained quite stable through the end of our sample period. Since the mid-1990s, we observe some evidence of polarization: the returns to unobserved skill declined at the bottom of the distribution while they remained relatively constant over the top half. (ii) The variance of unobserved skill changed very little across most cohorts in our sample (those born between 1925 and 1955). (iii) The variance of transitory shocks jumped up considerably in the early 1980s but shows little long-run trend otherwise over the more than thirty year period we study. (iv) The variance of permanent shocks declined very slightly over the 1970s, then rose systematically through the end of our sample by 15 to 20 log points. The increase in this variance over the 1980s and 1990s was strongest for workers with low unobserved ability. (v) In most years, the distribution of unobserved skill pricing is positively skewed, while the distributions of permanent and (especially) transitory shocks are negatively skewed.

download in pdf format
   (613 K)

email paper

Machine-readable bibliographic record - MARC, RIS, BibTeX

Document Object Identifier (DOI): 10.3386/w20068

Users who downloaded this paper also downloaded* these:
Andersson, Haltiwanger, Kutzbach, Pollakowski, and Weinberg w20066 Job Displacement and the Duration of Joblessness: The Role of Spatial Mismatch
Greenwood, Guner, Kocharkov, and Santos w19829 Marry Your Like: Assortative Mating and Income Inequality
Kerr, Kerr, and Lincoln w20069 Firms and the Economics of Skilled Immigration
Molloy, Smith, and Wozniak w20065 Declining Migration within the U.S.: The Role of the Labor Market
Kaplan, Violante, and Weidner w20073 The Wealthy Hand-to-Mouth
NBER Videos

National Bureau of Economic Research, 1050 Massachusetts Ave., Cambridge, MA 02138; 617-868-3900; email:

Contact Us