A Welding Procedure Specification (WPS) is a formal document describing welding procedures. It is an internal document used by welding companies to instruct welders (or welding operators) on how to achieve quality production welds that meet all relevant code requirements. Each company typically develops their own WPS for each material alloy and for each welding type used. Specific codes and/or engineering societies are often the driving force behind the development of a company's WPS. A WPS is supported by a Procedure Qualification Record (PQR or WPQR), a formal record of a test weld performed and rigorously tested to ensure that the procedure will produce a good weld. Individual welders are certified with a qualification test documented in a Welder Qualification Test Record (WQTR) that shows they have the understanding and demonstrated ability to work within the specified WPS.