The Raw Data Validation (RDV) processor performs low level validity checks on the raw data i.e. the data produced by the DAQ and calibration computers. It carries out a series of tests on the words in the raw data banks. There are a number of tests that RDV can apply. For example, the INTEGER test simply checks that an integer is within a specified range. Another test, MEAN_SD, does not check a single value of a word, but instead accumulates a mean and standard deviation, both of which are checked against limits during termination. Besides checking on individual words, RDV also performs a few data structure sequence tests, for example, requiring that a run header is the first data structure in the file. The tests on words and on sequencing is built into the processor. However the processor is designed to be extendible. The Program Notes section of the main execution routine RDV_RAW_DATA_VALIDATION gives details.