<p>The continuous growth of research knowledge and the demands for evidence-based practice have created a need to gather, analyse and synthesise previous research knowledge (Evans and Pearson 2001, Magarey 2001, Evans 2002, Jones 2004). The method of reviewing previous research can be referred to as ‘research of research’ (Droogan and Song 1996, Droogan and Cullum 1998, Whittemore 2005). Various methods can be used in a research review, depending on, for example, what the aim is of gathering and evaluating existing research knowledge, what kind of studies are included in the review and how they are analysed. The methods of reviewing existing research knowledge are integrative review, meta-analysis, systematic review and methods that combine qualitative research (for example, metasummary, metasynthesis, formal grounded theory and metastudy). What these different methods have in common is that they generally follow the strict methodological demands applied to research (Whittemore 2005).</p>