“…For instance, future research should contain control groups and differentiate the effects of multiple component interventions, psychological mediating processes (Hammer et al, 2005), pre/ postintervention data behavioral measures (Hammer et al, 2005;van Steenbergen et al, 2008), quasi/field/natural experimental designs (Hammer et al, 2005;Moen et al, 2011b;van Steenbergen et al, 2008), longitudinal data (Hammer et al, 2005;van Steenbergen et al, 2008), personality variables (van Steenbergen et al, 2008), randomized groups (Albertsen et al, 2014;Moen et al, 2011b), similar baselines between the groups (Albertsen et al, 2014), and large sample sizes (Giardini & Kabst, 2008;Martin & Sanders, 2003;Moen et al, 2011b). One issue when measuring the effects of interventions is time-lag, as some of the effects happen in the short-term and others in the long run (Albertsen et al, 2014;Hammer et al, 2011;Martin & Sanders, 2003;Moen et al, 2011b). A wait-list control group may be used to reduce feelings of unfairness among the intervention and control group (Albertsen et al, 2014;Michel et al, 2014).…”