"The systematic investigation into and study of materials and sources in order to establish facts and reach new conclusions" (OED, 2011, p. 1222).

"The systematic gathering and interpretation of information about individuals or organisations using the statistical and analytical methods and techniques of the applied sciences to gain insight or support decision making" (ESOMAR, 2013).

"A systematic process to solve real-world problems" (Gray, 2009, p. 2).

"Systematic investigation to find things out. It is the process by which we produce evidence or knowledge" (McGivern, 2006, p. 4).

"Systematic study and investigation" (Robson, 2011, p. 532).

"The systematic collection and interpretation of information with a clear purpose, to find things out" (Saunders et al., 2012, p. 600).

"An organised, systematic, critical, scientific inquiry or investigation into a specific problem, undertaken with the objective of finding answers or solutions thereto" (Sekaran and Bougie, 2010, p. 398).