editing - How do you avoid the problem of a collaborative work having separate voices?

I've not done collaborative writing before, but I've read several works, and sometimes the text strikes me as having a split personality: some parts were clearly written by one author, while others were written by another. (Note: I would give examples, but I can't remember any off-hand because I'm a bit sleep-deprived at the moment!)

So, the story itself is cohesive, but lacks a unified voice, so much so that it's distracting. Obviously, authors have very distinctive styles, and this can shine through very easily, so my question is really how do you ensure a unity of voice, or at the very least, incorporate the distinct voices of the authors in such a way that it isn't glaringly obvious that two different people were writing?

Would this come down to the editing process, or should you look at structuring the story in such a way that it can accommodate these different voices e.g. different narrators, POV's etc.?

Answer

For fiction that can accommodate different POVs, dividing those up per author not only addresses this problem but can be a feature.

For cases where you want a unified voice, if you can't get a tough editor like Lauren Ipsum suggested, try having the authors edit each other's sections. In technical-writing teams I've found that this drives the material toward the center; I have no experience doing this with fiction but would expect it to work. But first sit everybody down to have the "don't take this personally; it's about the work" conversation to reduce the chance of bruised egos.