That may be so on your case, but I've found in my experience that generally if a phone call is more productive than email it's because the topic at hand has not

That may be so on your case, but I've found in my experience that generally if a phone call is more productive than email it's because the topic at hand has not been developed enough to use a quick action based method to deal with the communication. I believe there are three situations in which a phone call is better than an email. A sales pitch, which would be a gazillion times more efficient if done face to face; a brainstorming conversation, which would be a lot better if it was divided in a solitary work period followed by a cumulative peer based review in person; and when there's a imperative need to switch directions ASAP, which will hinder productivity anyways however you look at it. Of course your millage may vary and I'm not trying to convince you your're wrong, specially because you aren't since this is a a topic very influences by personal preference. I just find that every instance where the telephone could outdo an email, is because either the parties involved where not properly prepared with the required resources in their possession, or because the type of communication was not meant to be written in the first place. Generally this last type works better in person. Almost always.