Comparing predictors of employment in Individual Placement and Support: A longitudinal analysis
Introduction
Individual Placement and Support (IPS) is an evidence-based model of vocational rehabilitation for clients with serious mental illness that has proven effective across a range of populations (Modini et al., 2016). Despite many prediction studies, a comprehensive picture of the relationships between commonly available client, program, and environmental characteristics and IPS employment outcomes remains elusive (Bond and Drake, 2008b, Campbell et al., 2010b). Research has demonstrated that factors including duration of enrollment in IPS, client characteristics, local economic conditions, and the quality of a program's implementation, can influence employment outcomes (Drake et al., 2016). However, the relative contributions of these domains in explaining employment have been explored in piecemeal fashion, and no analysis has yet combined all of them and assessed their effects and relative contributions in a single model.
Findings regarding relatively weak predictors are highly sensitive to study design, analytic technique, and power. Predictors of work outcomes among people with serious mental illness include baseline client characteristics such as cognitive difficulties and symptom severity (Anthony et al., 2002, Bond and Drake, 2008a, Campbell et al., 2010a, Cook and Razzano, 2000, Green, 1996, Hoffmann and Kupper, 1997, McGurk and Mueser, 2004, Michon et al., 2005, Razzano et al., 2005, Rosenheck et al., 2006, Strauss and Carpenter, 1974, Tsang et al., 2010, Wewiorski and Fabian, 2004), environmental factors such as local unemployment rate (Burns et al., 2007, Cook et al., 2006) and rurality (Haslett et al., 2011), program factors such as IPS fidelity (Bond et al., 2011), intensity of IPS services (Bond and Kukla, 2011), receipt of Social Security Disability Insurance benefits (Rosenheck et al., 2006), and histories of work (Metcalfe et al., 2017, Strauss and Carpenter, 1974). Furthermore, prior research has suggested that predictors of employment outcomes for those who receive IPS differ from those who do not (Campbell et al., 2010b). A prior analysis of some of these predictors in the full Mental Health Treatment Study sample did not control for duration of participation, environmental variables, or IPS fidelity (Metcalfe et al., 2017). The straightforward solution to this fragmentary approach is to conduct a single simultaneous analysis of all available predictors using a sufficiently large sample of IPS recipients.
The primary purpose of this analysis was to compare predictors of employment in the presence of effective employment and mental health services. We determined the effects and relative importance of client characteristics, IPS fidelity, and local economic factors in a multivariable model of quarterly competitive employment among IPS recipients. The large sample size and diversity of sites in the Mental Health Treatment Study enabled inclusion of variables specific to both clients and IPS programs in statistical models of quarterly employment status.
Section snippets
Overview
We conducted a secondary analysis of participants in the intervention arm of the Mental Health Treatment Study, a multisite randomized controlled trial comparing the effectiveness of an intervention group receiving comprehensive services that included IPS, systematic medication management (evidence-based pharmacological management guidelines), and other behavioral services to a treatment-as-usual control group at 23 sites (Drake et al., 2013). We assessed the effect size, significance, and
Results
Table 1 contains correlations of baseline client- and site-specific covariates, as well as site-specific process measures, with total number of quarters worked during eight quarters of follow-up. Competitive employment correlated significantly (α = 0.002) with having worked within two years of baseline, having spent less time as a Social Security beneficiary, being Hispanic, and having higher cognitive function.
Fig. 1 shows the competitive employment status over eight quarters of follow-up
Discussion
In this analysis of Social Security Disability Income beneficiaries receiving IPS supported employment, work history, years as a beneficiary, and neurocognitive function were the best predictors of employment outcomes, and their effects were consistent throughout follow-up. As these results make clear, a model containing statistically significant factors, even those corresponding to apparently large effect sizes, did not explain a large fraction of the observed outcome variance and enable
Conflict of interest
None.
Acknowledgments
The authors thank Susan Kalasunas from the U.S. Social Security Administration (SSA) for assistance. This study extends work that was conducted under contract SS00-05-60072 between the SSA and Westat and grant #H133B140028 from the National Institute on Disability, Independent Living, and Rehabilitation Research (NIDILRR). The opinions expressed in this article are those of the authors and not necessarily those of the SSA.
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