When you start a project, not just outsourcing but any project, it's always good to remember the old saying, "You don't know what you don't know!" It's true... and obvious. When you enter a new territory that are you are unfamiliar with, it's easy to make mistakes simply because you don't know how things work. But what about what you do know... but don't know that you know it?
In education there is a term, "Tacit Knowledge," that addresses the vast amount of undocumented knowledge that we all use, but generally forget that we know. All tacit knowledge is culturally specific. The things that you just know" are not the same as the things that someone else (from a different culture, location, social strata, etc.) knows. This applies to the most fundamental things in your environment.
Let me give you an example. In the US, we know that GREEN is good and RED is bad. Red is the color of: a stop sign, the down button on an elevator, flames or fire, and negative numbers on a spreadsheet. Green is: an environmentally friendly company, the up button on an elevator, the go light at an intersection, and the color of a fire exit. Wait... what was that last one? Fire exit... green? But everyone knows that fire exits, fire extinguishers, and FIRE are all red! However, if you go to the UK... which is culturally very similar to the US... fire exits are green. US: fire is bad; fire exit is red. UK: getting away from fire is good (and safe); fire exit is green. Both are reasonable interpretations, but if you are in a fire situation, you want to be really clear on whether you're supposed to run towards the vague red light or the vague green light that you think you see through the smoke, off in the distance.
When you outsource, to a different city in the same country, or even a different firm in the same city, a huge amount of tacit information can be lost. Of course, the further the move, the greater the tacit knowledge gap. Don't underestimate tacit knowledge, it could be the difference between success and failure for your project.