Temporary work and depressive symptoms: A propensity score analysis

https://doi.org/10.1016/j.socscimed.2010.02.008Get rights and content

Abstract

Recent decades have seen a tremendous increase in the complexity of work arrangements, through job sharing, flexible hours, career breaks, compressed work weeks, shift work, reduced job security, and part-time, contract and temporary work. In this study, we focus on one specific group of workers that arguably most embodies non-standard employment, namely temporary workers, and estimate the effect of this type of employment on depressive symptom severity. Accounting for the possibility of mental health selection into temporary work through propensity score analysis, we isolate the direct effects of temporary work on depressive symptoms with varying lags of time since exposure. We use prospective data from the U.S. National Longitudinal Survey of Youth 1979 (NLSY79), which has followed, longitudinally, from 1979 to the present, a nationally representative cohort of American men and women between 14 and 22 years of age in 1979. Three propensity score models were estimated, to capture the effect of different time lags (immediately following exposure, and 2 and 4 years post exposure) between the period of exposure to the outcome. The only significant effects were found among those who had been exposed to temporary work in the two years preceding the outcome measurement. These workers report 1.803 additional depressive symptoms from having experienced this work status (than if they had not been exposed). Moreover, this difference is both statistically and substantively significant, as it represents a 50% increase from the average level of depressive symptoms in this population.

Section snippets

Data

We use prospective data from the U.S. National Longitudinal Survey of Youth 1979 (NLSY79), which has followed, longitudinally, from 1979 to the present, a nationally representative cohort of American men and women between 14 and 22 years of age in 1979. Details on the survey methodology have been described elsewhere (Zagorsky & White, 1999). Our sample is based on longitudinal records from this dataset collected biennially between 1992 and 2002. Data are publicly available online and were

Temporary work

In 1994, 1995, and 1998, questions based on the Supplement on Contingent Work of the Current Population Survey (CPS) were fielded, and detailed information was collected on up to five jobs in the period since last interview. Temporary work exposure was based on self-reported answers to the following question: “[Are/Were] you a regular employee at this job, do you consider yourself a temp worker, consultant or contractor, or are you an employee of a contractor? By “THIS JOB”, we mean the one you

Propensity score analyses

We follow the strategy described by Oakes and Johnson (2006) and use psmatch2 in Stata 10 for our analyses (Leuven & Sianesi, 2003). As mentioned in the introduction, temporary workers may differ substantially from permanent workers in a number of ways, one of them being that they may be selected into these positions as a result of pre-existing poor mental health. This situation can pose a problem with methods that simply control for confounders, as they assume overlapping distributions of

Model 1

Table 2 presents the results of the matching process for Model 1. For each predictor, the averages among temporary workers and non-temporary workers are presented, before and after matching. As the standardized differences in the fifth column indicate, most of the differences are well below 10%, with race and age just above that cut-off point. All the predictors saw an improvement in the bias as a consequence of matching, as indicated by the uniformly positive column of % of reduction in bias.

Discussion

This study finds an important increase in depression symptom severity associated with exposure to temporary work at any point in time in the two preceding years (including concurrently). Most importantly, these results were obtained through propensity score matching on a number of covariates affecting the likelihood of temporary work status, including, most notably, prior depressive symptoms. Moreover, the exposed group was limited to workers who reported temporary employment status, and did

Acknowledgements

We are grateful for assistance from Tania Jenkins and comments from Thomas DiPrete and reviewers. We acknowledge funding support from Canadian Institutes for Health Research grant MOP77800 (PI: Quesnel-Vallée) and a salary award from the Fonds de recherche en santé du Québec to Quesnel-Vallée.

References (33)

  • M. Kim et al.

    Is precarious employment damaging to self-rated health? Results of propensity score matching methods, using longitudinal data in South Korea

    Social Science & Medicine

    (2008)
  • K. Barker et al.

    Controversy and challenges raised by contingent work arrangements

  • R. Barnes

    Motivation and work motion and time study, design and measurement of work

    (1980)
  • D. Belman et al.

    Nonstandard and contingent employment: contrasts by job type, industry and occupation

  • C. Bernhard-Oettel et al.

    Comparing three alternative types of employment with permanent full-time work: how do employment contract and perceived job conditions relate to health complaints?

    Work & Stress

    (2005)
  • C. Casey et al.

    ‘Just a temp?’ Women, temporary employment and lifestyle

    Work, Employment and Society

    (2004)
  • S. Cohany et al.

    Counting the workers: results of a first survey

  • B. Dohrenwend et al.

    Socioeconomic status and psychiatric disorders: the causation-selection issue

    Science

    (1992)
  • M. Eliasson et al.

    Latent or lasting scars: Swedish evidence on the long-term effects of job displacement

    Journal of Labor Economics

    (2006)
  • J. Ferrie et al.

    Effects of chronic job insecurity and change in job security on self reported health, minor psychiatric morbidity, physiological measures, and health related behaviours in British civil servants: the Whitehall II study

    Journal of Epidemiology and Community Health

    (2002)
  • D. Friedland et al.

    Underemployment: consequences for the health and well-being of workers

    American Journal of Community Psychology

    (2003)
  • W. Hadden et al.

    A glossary for the social epidemiology of work organization: part 3, terms from the sociology of labour markets

    Journal of Epidemiology and Community Health

    (2007)
  • W. Heinz

    From work trajectories to negotiated careers – the contingent work life course

  • S. Hipple

    Contingent work in the late-1990s

    Monthly Labour Review

    (2001)
  • I. Kawachi

    Globalization and workers’ health

    Industrial Health

    (2008)
  • E. Leuven et al.

    PSMATCH2: Stata module to perform full Mahalanobis and propensity score matching, common support graphing, and covariate imbalance testing

    (2003)
  • Cited by (96)

    View all citing articles on Scopus
    View full text