This research addresses the lack of an existing psychometrically sound Asperger’s Syndrome self-screening instrument for adults. Initial instrument development procedures were carried out by creating an item pool using existing Asperger measures. Items were rewritten following common item writing rules suggested by several researchers as reference. Five new domains were created and the items were re-categorized. Expert panel of nine judges specialized in Psychometrics, ASD, School Psychology, and Speech-Language Pathology were asked to rate the relevancy of items to their domains in order to obtain evidence of content validity. These experts were chosen because of their relatedness to Asperger’s Syndrome and their expertise in instrument development. First, the quality of the judges’ ratings were examined to identify any aberrant judges. Ratings were then analyzed using the remaining six judges using three descriptive and three quantitative methods to examine the representativeness and relevancy of each item to their domain. A total of 55 items were identified as satisfactory by the judges. The second part of this study was to compare the content validity analytical methods. It was concluded that the percentage agreement, the content validity index (CVI), and the content validity coefficients (VIK) were the best methods to use in selecting the satisfactory items. This research aims to bring more attention to the importance of psychometric properties in measures for the Autism Spectrum Disorder field. It also hope to shed some light on which content validity analyses would best be used under certain circumstances. Limitations of study and future directions were also discussed