The dance for transferring from Schengen flights to US flights goes something like this:

• Exit into the common airside area (for departing/arriving passengers) of the Schengen part of the terminal (equivalent to "domestic")
• Proceed to exit immigration procedures airside, meaning you do not collect your bags nor do you go landside, you will simply be "exiting" the Schengen region (follow signs for transfers and/or the pier letter of your next flight that will invariably lead you to immigration)
• There is no customs screening
• Proceed to the gate
• Buy some things along the way to help prove running a shopping mall is more lucrative than running an airport
• Queue for screening; they will ask you all sorts of questions about where you live, what you do, electronics you have taken with you etc. etc.
• Immediately proceed through security at the gate itself
• Wait for boarding to start in the enclosed waiting area (with restroom facilities)
• Queue on the aircraft while people debate which magazine to read before finding a spot for their kitchen sink.

All US-bound flights have extra screening measures in place, and all passengers must go through the scatter x-ray devices (or get a very intimate pat down). There is a priority line for business class and elite passengers for the screening part, but there seems to be no priority for security once they have started the security part of boarding. Once through the screening process, you cannot leave the gate area.

Because of all the queuing and waiting and extra procedures, my strategy for US-bound flights has been to wait until the last possible moment to board. That way I never have to wait, but I can stroll through screening, security and boarding. I then peek onto the jetway and invariably find there is still a queue waiting to board the aircraft. So I take a seat in the enclosed waiting area, taking the time to organise my carry-on items and taking out things I will use during the flight. I've never had a problem; my name has never been called out and my bags never threatened with off-loading and/or destruction.

The reason for non-centralised security in the non-Schengen part of Schiphol airport has to do with the mixing of arriving and departing passengers. Specifically it concerns the arriving of passengers from areas of the world with less than reliable and trustworthy airport security; EU law invariably demands these passengers be re-screened. Schiphol has plans to eventually separate arriving and departing passengers, to subsequently introduce centralised security. However, this is still in the planning stages and some years off.