The RAADS-R is a modified version of the Ritvo Autism Asperger's Diagnostic Scale (Ritvo et al. 2008). The rationale for its development was the need for a clinical adjunct diagnostic tool. While several diagnostic scales for children and adolescents with ASD are available, only one peer- reviewed scale, The Autism-Spectrum Quotient (AQ) was designed specifically for adults. It's authors emphasize that it is useful in identifying autistic traits and as a screening instrument but not as a diagnostic tool.
This test is designed to be administered by a clinician in a clinical setting and as such is of limited use for self diagnosis. At the very least, take this test with the assistance of someone who knows you well. If you suspect you may have an autism related disorder such as Asperger's Syndrome, by all means take this test but do not rely on the results as absolute proof either way.