Specifying the characteristics of TASW

First, the facet of TASW that is probably most difficult to determine is the time frame. The interpretation of time specifications such as “after-hours,” “outside of typical working time,” “after regular working hours,” “nonwork hours,” and “family time” is largely delegated to study participants and readers in most studies. It remains unclear when “working time” starts and ends. Fenner and Renn (Reference Fenner and Renn2004) suggest that “normal” working hours are characterized by a minimum of 40 hours per week and that these are over when employees’ colleagues leave the office at the end of a typical workday. With the increasing prevalence of flexible work arrangements and telecommuting, this definition does not seem applicable anymore. A possible solution is presented by Arlinghaus and Nachreiner (Reference Arlinghaus and Nachreiner2014), who suggest that supplemental work occurs “in the form of any work activity during any planned free time” (p. 2). Furthermore, it remains unclear whether TASW is limited to hours after work or can also happen before (e.g., checking e-mails during breakfast) or between work hours (e.g., making business phone calls during breaks). So far, studies have mostly focused on TASW in the afternoon or evening. Overall, a clear definition of when regular working time ends and when supplemental work begins is currently lacking.

Second, another key facet of TASW is the content of work behavior. According to Fenner and Renn (Reference Fenner and Renn2004), TASW involves performing role-prescribed tasks. Most studies refer to the use of ICTs for work-related purposes in general, without further specifications. Others focus on work-related contacts, connectedness, or mere availability (Ďuranová & Ohly, Reference Ďuranová and Ohly2016). Some scales contain various behaviors like availability, checking behavior, and responding to messages (e.g., smartphone use scale; Derks et al., Reference Derks, van Duin, Tims and Bakker2015). It is not clear whether all these behaviors really qualify as TASW. Future research thus needs to evaluate potential conceptual differences between active ICT behaviors like email-checking and making phone calls and more passive ICT behaviors like availability or connectedness. So far, it has also not been defined whether tasks ranging at the border between private and work life, such as chatting with colleagues (e.g., via Slack) or administering one’s LinkedIn profile, count as TASW.

Third, the place where employees engage in TASW needs to be clarified. It is unclear whether TASW can happen independent of a specific place or whether it is restricted to the home domain. Fenner and Renn (Reference Fenner and Renn2004) state that TASW is performed “from home or away from work when on holiday” (p. 181). Most studies adopt this definition and focus on TASW happening at home (e.g., Wang et al., Reference Wang, Chen and Duan2017), whereas other studies offer no further specification of the place (e.g., Derks et al., Reference Derks, van Duin, Tims and Bakker2015). It thus needs to be clarified whether other locations (e.g., restaurants, parks), the commute, or even the office (after official working hours) can be considered places to engage in TASW.

Fourth, the compensation for TASW remains to be clarified. According to Fenner and Renn (Reference Fenner and Renn2010), TASW is not covered by a formal contract or compensation agreement. So far, studies on the topic provide no information on potential compensation of employees for their work-related ICT use after-hours. We encourage researchers to critically evaluate this facet of TASW. On one hand, time off in return for TASW could reduce the total working time to a regular level. On the other hand, TASW still expands the working time on a specific day beyond a normal level. Extra pay as compensation for TASW does not affect working time at all. In this respect, it could be interesting to examine differences in the relationships between TASW and employee outcomes (e.g., well-being) under diverse compensation conditions.

Finally, the target group of TASW needs to be carefully considered. In their definition of TASW, Fenner and Renn (Reference Fenner and Renn2010) focus on full-time employed professional or white-collar workers. However, studies on the topic have also included part-time workers because qualitative research showed that part-time workers also engage in work-related ICT use after hours (Eichberg et al., Reference Eichberger, Derks and Zacher2021). It is conceivable that engaging in TASW is even more relevant for those working part time because they might be contacted by their full-time colleagues during nonwork hours and feel the need to check their messages to not miss information. Furthermore, limiting TASW to white-collar workers should also be reconsidered because non-office-based employees like teachers and even builders can engage in TASW (e.g., preparing lessons, writing invoices). Thus, researchers should discuss the expansion of the TASW definition to professions besides white-collar workers. It would be particularly interesting to compare differences in the experience of TASW in different occupations.

(Technology-assisted) supplemental work

We further consider it important to take a critical look at the technological foundation of TASW. By definition, TASW is accomplished with the help of technological tools. Studies on the topic either consider technology-use in general (e.g., Eichberg et al., Reference Eichberger, Derks and Zacher2021) or focus on specific communication media like smartphones (e.g., Derks et al., Reference Derks, van Duin, Tims and Bakker2015). In their focal article, Hu et al. (Reference Hu, Barber, Park and Day2021) raise the concern that ICT concepts might just be a relabeling of nontechnological concepts that are already well researched. We argue that neither TASW nor its nontechnological equivalent, supplemental work, have already been researched sufficiently. However, we challenge the assumption that TASW is conceptually different from supplemental work. Technological devices are a frequently used means to engage in supplemental work. However, nontechnological forms of supplemental work (e.g., reading a printed paper or book, filing documents) are also possible. The question is whether TASW and supplemental work are distinct constructs that are differently associated with various antecedents and outcomes. In contrast to TASW, research on supplemental work (without a technological component) is rather scarce or even nonexistent. The definition of supplemental work resembles the one of TASW, except that supplemental work may include the use of technology, but it is not obligatory (Venkatesh & Vitalari, Reference Venkatesh and Vitalari1992). Researchers need to clarify whether it is worthwhile pursuing two paths of research (i.e., supplemental work and TASW). It might be more feasible to sharpen the existing definition of TASW, as described above, and extend it to nontechnological work. To make this decision, it would be helpful to conduct confirmatory factor analyses of respective measurement scales and to compare the antecedents and outcomes of TASW and supplemental work. In case there are differences, supplemental work and TASW need to persist as distinct constructs. If not, these two constructs could be merged.