There is a description of the NVR tests and what they are testing for on the NFER site..
http://www.nfer.ac.uk/nfer/index.cfm?20 ... F32480C310
Here are two extracts....
In an educational context, these tests are typically used as an indication of a pupilâ€™s ability to understand and assimilate novel information independently of language skills. Scores on these tests can indicate a pupilâ€™s ability to learn new material in a wide range of school subjects based on their current levels of functioning
Cattell (1963) however, defined NVR as a â€˜fluid-general intelligenceâ€™, which involves the ability to reason with novel material, without the need to draw on learned knowledge. Cattell believed measures such as NVR tests could be considered â€˜culture fairâ€™ and thus provide a more appropriate measure of general intelligence, compared with verbal reasoning tests, for test takers not fluent in the language being used.