Actuarial literature with an emphasis on net trend

Greetings Go Actuaries!

Is there any commonly accepted, perhaps even, on a syllabus actuarial literature that supports using net trend as a guiding principle when making actuarial selections?

Sure, during the indication process we need to select, distinctly, loss frequency, loss severity, and premium trend(possibly exposure trend depending on the line i suppose). But is there any actuarial literature which supports the process of backing into a reasonable net trend? Like, you may select premium and severity trend per normal, but you may select frequency trend counter to some of the data, to end up at a reasonable net trend?

I suspect this is an issue primarily with low credibility lines, as larger lines should have data in the premium and loss trend selections to make those selections in a vacuum, but still produce reasonable net trend results.

Till all are one,

Epistemus

(1+freq)(1+sev)/(1+prem) -1 = net trend

how you select each trend is a science in itself, including but not limited to how credible each trend is, business mix shift, etc.