The procedure to derive an FSIQ from results from these tests is too complicated to present a table that directly converts composite raw scores to FSIQs.
To derive an FSIQ from sub-test scores, subtract 100 from both scores and place them into this formula: (.58(x+y))+100. For example, a Verbal score of 137 and a Non-verbal score of 142, when being converted to an FSIQ, should appear as such: (.58(37+42))+100
. The resulting FSIQ from this example would be 145. The minimum and maximum scores on this test are 43 and 155. To see the rarity of a particular score, visit this page. The two sub-tests have a moderately high positive correlation (.58), and correlate with FSIQs very highly. Scores on the Non-verbal test have a .89 correlation with FSIQs, and scores on the Verbal test have a .88 correlation with FSIQs. The two tests have a common factor loading of .76.
This test was developed to be very similar to the WASI-II (FSIQ-2), which is an abbreviated form of the WAIS-IV, which is considered to be the gold standard of IQ tests. Moreover, in a very small, preliminary sample, PDIT FSIQs had a .85 correlation with WAIS-IV FSIQs. The raw data used to obtain these statistics can be viewed
here, and a 9-page paper that examines statistics regarding this test, and provides an overview of the methods and theories behind the construction of the test, can be viewed
here.
Furthermore, although this test, if done properly appears to provide a reasonably accurate measure of general intellectual ability, it is not uncommon for individuals to get slightly, and even moderately different results on assessments that correlate highly when many scores are considered.