Background and Rationale
Given the serious hazards inherently associated with the occupation of warfighting, military service provides an ideal context for studying resilience. Numerous longitudinal studies have mapped distinct adjustment patterns (i.e., trajectories) among military service members (MSMs) following combat deployment. While these studies have shown that a resilient trajectory is the most common response following deployment (Bonanno et al., 2012; Polusny et al., 2017; Porter et al., 2017), few prospective studies have investigated trajectories of positive adaptation among young recruits beginning early in their military career (Sefidan et al., 2021). Thus, young military recruits who have recently enlisted and not yet shipped to Basic Combat Training (BCT) provide an especially important population for studying resilience because they have not yet been exposed to military-related stressors, and findings could help guide the development of interventions for young recruits (Polusny & Erbes, 2023).
Although it has become fairly common practice to conduct resilience research with military populations (Galatzer-Levy et al., 2018), most existing studies have relied nearly exclusively on self-report. Although invaluable to research, reliance on self-report measurement alone is associated with a number of limitations, including potential for systematic nonresponse bias and monomethod bias (Doty & Glick, 1998; Semmer et al., 2003). While prospective, longitudinal studies of resilience are beginning to incorporate multilevel approaches (Crane et al., 2012; Schmidt et al., 2015), including neuroimaging data (Roeckner et al., 2021), very few have focused on young military recruits at the onset of their careers (Smaliukienė et al., 2022). To unravel mechanisms contributing to resilience in young recruits, we have planned a large-scale prospective, longitudinal investigation with an embedded laboratory sub-study that will incorporate clinical interview, neurocognitive testing data, and DNA sampling.
Because large, prospective, longitudinal studies – such as the study we have planned – are costly and resource-intensive endeavors, it is vital to first determine the feasibility of proposed study methods that have not been previously tested. While our team has a long history of successfully conducting longitudinal studies with National Guard soldiers in the context of military deployment (Erbes et al., 2017; Ferrier-Auerbach et al., 2010a; Polusny et al., 2009, 2017), we are uncertain regarding the feasibility of recruiting and retaining a cohort of younger military recruits (most of whom are age 18). Studies of health and wellbeing in emerging and young adult populations suggest that these age groups may be especially difficult to recruit for longitudinal studies (Lystad et al., 2022). Previous research has also shown that attrition from longitudinal studies is highest among younger adults, especially those with less education (Young et al., 2006). Some researchers theorize that these age groups are difficult to recruit and retain because emerging adulthood is a period of change, instability, and a desire to socially conform which may pose barriers to research participation (Hanna et al., 2014).
In recent years, longitudinal researchers have shifted away from using well established mailed survey methodology and have increasingly adopted electronic survey methods (e.g., collection of self-administered electronic surveys by email) (Millar & Dillman, 2011). While mailed survey methods have historically yielded excellent response rates (~ 65–80%) (Polusny et al., 2017), this method has considerably greater costs (i.e., paper, postage, mailout, and data entry costs). Electronic survey methods have benefits in terms of convenience, accessibility, and reduced need for staffing and data entry. However, the use of online platforms (i.e., Qualtrics) is not without challenges. Results of meta-analyses indicate that online surveys generally have lower response rates (about 20% lower on the average) than traditional mailed surveys(Daikeler et al., 2020; Shih & Fan, 2009), but some studies suggest that online surveys of young adults may yield higher response rates when participants are initially mailed an invitation to complete an online survey with the option of completing the paper form (Lallukka et al., 2020; Larson et al., 2011).
Few longitudinal studies have incorporated performance-based neurocognitive tests or embedded laboratory methods to evaluate potential mechanisms underlying resilience. Computerized neurocognitive tests, such as the Penn Computerized Neurocognitive Battery (CNB), are now available allowing longitudinal researchers to capture and integrate such data within large longitudinal studies (Moore et al., 2015a). However, the Penn CNB was not originally designed to be administered remotely or on personal devices (Gur et al., 2010), and at the time of this study, test developers recommended that a proctor assist with test administration to troubleshoot any problems the participant may encounter when attempting to access the instrument via their own electronic device. Thus, the feasibility of collecting Penn CNB data from groups of participants in a classroom setting at military installations was unclear, as was the feasibility of participants completing the Penn CNB on their personal devices. While embedded laboratory methods provide valuable opportunities to richly characterize participants, collecting data at laboratory visits places a high burden on participants and can be very costly to conduct. Given requirements of the planned large-scale prospective study to collect extensive laboratory data from participants between baseline assessment and participants’ pending departure for BCT, the feasibility of recruiting participants to take part in the laboratory sub-study as well as collecting complete data in a timely manner was also unclear.
To reduce potential biases associated with reliance on retrospective self-reports, resilience studies ideally collect data characterizing participants’ experience of stressor exposure as close in time as feasible to the actual events. We are aware of few studies conducted by civilian researchers in which data were collected from military personnel while deployed to a combat zone or during military training (Ferrier-Auerbach et al., 2010a). Therefore, we are uncertain about the feasibility of collecting brief survey data from participants during BCT.
Study Objective
This study aims to assess the feasibility of our study methods in preparation for a future large-scale prospective, longitudinal study. We conducted a 12-month study to evaluate the feasibility of subject recruitment and retention procedures for the longitudinal study and an intensive laboratory sub-study. We pilot tested procedures for collecting neurobehavioral data using web-based surveys that incorporated performance-based neurocognitive testing before and after BCT. We also assessed the viability of obtaining comprehensive neurobiological measurements in a laboratory setting before and after BCT. Furthermore, we explored the feasibility of collecting stressor exposure data during participants' time at BCT and examined the availability of administrative data for study participants.