Continuing with what Nils said, the article mentioning the outMsg also discusses another approach mainly the Translator approach. http://folkertdev.nl/blog/elm-child-parent-communication-continued/

This is another possibility that we actually have tried but decided not to use (good to stick with one approach to avoid confusion).

If you think that there is too much boilerplate while using OutMsgs, there is actually a library that reduces most of it at github http://package.elm-lang.org/packages/folkertdev/outmessage/1.0.1/