Here is a list of things that anyone can observe easily when visiting a Chinese factory:

Is the production floor clean? Are products in direct contact with the ground?
Is the office organized? Or do they have papers all over their desks?
Are the workers’ toilets clean?
Are there lines on the ground, and nameplates for each department?
Do the workers wear protective equipment (masks, gloves…) when they perform dangerous operations?
Are the operators afraid/nervous when you stop and look at them?
Do the workers perform only 1 simple and repetitive operation, in front of a conveyor belt?
Is production organized in islands (bad) or in line (better)? Is there a lot of work-in-process in the workshop? (You can read about the different types of production organization).
What operations are they performing? If it is only packing, you are wasting your time (the real action is somewhere else).
What other customers do they serve in your country? Have a look at the labels on the packing line, and then at the shipping marks in the cartons warehouse.
Do they agree to show you the latest designs they developed for their other customers? Would they give you quotations for these proprietary designs?
Does the showroom contain branded items? If some designs were developed for a specific customer, would they accept to make them for you too?
To finish on a lighter note: make sure you don’t go as far as the pointy-haired boss in the below cartoon.
Inspecion service in China [www.china-inspections.com]