“…Investigating data quality and modeling answer behaviour can be done by using item response models (Bolt & Johnson, 2009;De Jong, Steenkamp, Fox, & Baumgartner, 2008;Tijmstra, Bolsinova, & Jeon, 2018;Zickar, Gibby, & Robie, 2004), latent class models (Van Rosmalen et al, 2010), multitrait multimethod (MTMM) data (Andrews, 1984;Campbell & Fiske, 1959;Hox, 1995;Saris & Gallhofer, 2000Saris, Revilla, Krosnick, & Shaeffer, 2010;Saris, Satorra, & Coenders, 2004;Scherpenzeel, 1995;Scherpenzeel & Saris, 1997), multilevel models (Beretvas, 2011;Fielding & Goldstein, 2006;Gummer & RoĂmann, 2014;Leckie, 2019;Olson & Smyth, 2015;Olson, Smyth, & Ganshert, 2019;Raudenbush & Bryk, 2002), or a combination of the two latter (Maas, Lensvelt-Mulders, & Hox, 2009). We need to note that we do not use a customary statistical method for the main part of this thesis.…”