Everytime I am creating a artificial story to justify the reason for choosing the title compound. One word answer is through literature survey. I guess most of the researchers select the title compounds from literature survey.
What exactly do you mean by "title compound"? For example, https://en.wikipedia.org/wiki/Compound_(linguistics)? Do you mean a "compound title" (cf. e.g. http://tvtropes.org/pmwiki/pmwiki.php/Main/CompoundTitle).
Irrespective of this, if what you mean is to form a concept or sentence from other concepts or sentences, then I would say that you perform some kind of qualitative analysis. In my view, some people confuse the qualitative analysis with a literature survey; a qualitative analysis is typically part of a literature survey. Have a look at chapter 4 and section 5.4 in Wohlin, C et al. 2012, Experimentation in software engineering, Springer, New York or chapter 18 in Oates, BJ 2006, Researching information systems and computing, SAGE Publications, London ; Thousand Oaks, Calif.