Date Published: May 1, 2019
Publisher: Public Library of Science
Author(s): Britta Gauly, Clemens M. Lechner, Timo Gnambs.
Can participation in job-related training contribute to the formation and maintenance of adults’ literacy skills? Although evidence suggests that participation in training is related to higher literacy skills, it remains unclear whether this association reflects a causal effect of training participation on literacy (training effects), results from the self-selection of more high-skilled individuals into training (selection effects), or is due to other sources of endogeneity (e.g., omitted variable bias). To unravel these possibilities, we used data from the Programme for the International Assessment of Adult Competencies (PIAAC) and its German follow-up, PIAAC-Longitudinal (PIAAC-L). As these unique data offer repeated measures of literacy skills, spaced three years apart, in a large and representative sample, they allowed us to disentangle training effects from selection effects and to account for potential endogeneity. Analyses revealed that, even after taking account of formal education and a host of job characteristics, individuals with higher literacy skills were more likely to participate in training. By contrast, no evidence for effects of training on literacy skills emerged in any of our models, which comprised lagged-dependent, fixed effects, and instrumental-variable models. These findings suggest that, rather than job-related training contributing to literacy development, individuals with higher literacy skills are more likely to participate in training.
As the old adage goes, “you can’t teach an old dog new tricks.” Or can you? This question is central to research on lifelong learning in the workplace. Here, researchers ask what occupational factors contribute to the formation or maintenance of worker’s individual skills after finishing formal education [1–3]. In the light of the growing pace of technological innovation and the demographic challenge of an ageing workforce, this question is particularly relevant both for individuals themselves (e.g., for maintaining employment prospects) and for society at large (e.g., in terms of economic growth) [4, 5].
The aim of the present study was to unravel the positive relationship between job-related training and literacy skills reported in previous studies [8, 10, 11]. Our guiding question in this regard was whether this relationship signifies that training participation fosters literacy skills (i.e., training effects) or whether it, reflects the higher propensity of more high-skilled individuals to participate in further training (i.e., selection effects or reverse causation) and/or the presence of confounding factors that influence both training participation and literacy (i.e., omitted variable bias).
Can participation in job-related training contribute to the formation and maintenance of adults’ literacy skills? Frequently reported associations between participation in job-related training and higher literacy skills [8, 10, 11] suggest that this is the case. However, as we argued, this association between training and literacy may reflect more than one of several equally plausible (and not mutually exclusive) directions of influence: On the one hand, job-related training—even types of training intended to impart highly job-specific or firm-specific skills—may indeed exert positive spill-over effects on the development of literacy skills (i.e., training effects). On the other hand, workers may select themselves into job-related training based on their level of literacy skills, whereby those with higher levels of skills are more likely to participate in further training (i.e., selection effects). In addition to selection based on literacy skills, further sources of endogeneity such as omitted third variables that influence both training participation and literacy skills may bias estimates of purported training effects. In the present study, we set out to unravel these possibilities, analyzing whether the association between training and literacy reflects training effects or rather selection and other sources of endogeneity. For this purpose, we used unique two-wave panel data from two representative large-scale surveys representing the German population between 16 and 65 years and offering repeated, and high-quality, measures of literacy skills. In doing so, our study is the first to analyze the relationship between job-related training and literacy using repeated-measures data and objective literacy measures that cover the entire range of skills from very elementary to high.
The key contribution of our study is to answer the question as to whether the frequently observed (e.g., [8, 10, 11]) positive association between participation in job-related training and literacy skills reflects causation (i.e., training effects on literacy skills) or selection (i.e., effects of literacy skills on training participation), or whether it is due to other sources of endogeneity, such as omitted variable bias. In this regard, our findings suggest that selection effects dominate the picture: Individuals with higher literacy skills were more likely to participate in job-related training, even after controlling for formal education and a host of job characteristics. Contrariwise, we found no evidence of a causal effect of training on literacy skills over the three-year period under study—at least not with regard to way in which training and skills are defined and measured in the context of PIAAC. These results do not imply that job-related training has no beneficial effects whatsoever for participants and employers. On the contrary, we have taken it for granted throughout this article that job-related training contributes to job-specific or firm-specific skills—that is, idiosyncratic skills that cannot be assessed in large-scale studies such as PIAAC. If training did not successfully contribute to the formation of job-specific skills, employers would surely be unwilling to finance it and employees would be equally unwilling to participate in it. Moreover, several studies that controlled for unobserved selection and unobserved heterogeneity have shown that, under certain conditions, participation in training can lead to wage premiums or increased employment prospects. However, as far as general literacy skills are concerned, our data provide no evidence for causal training effects. In other words, literacy skill gains through specific job-related training not designed to foster literacy in the sense of a spillover effect do not appear to be likely. For policymakers and practitioners interested in fostering literacy skills, training that is specifically designed to foster such skills is likely to be a more suitable option.