Indiana University-Purdue University Indianapolis (IUPUI) / Factor H is a newly identified phenomenon which describes a constellation of attributes of the new graduate nurse reflecting personality traits, intellectual abilities, and clinical judgment. In a previous pilot study conducted by this researcher nurse managers and experienced Registered Nurse (RN) preceptors described characteristics demonstrated by new graduate nurses demonstrating Factor H and the new graduate nurse’s ability to transition quickly and successfully into the RN role in the acute care environment. There is currently no instrument available to measure this phenomenon. The specific aim of this research was to develop and psychometrically test a scale designed to identify the presence of attributes of Factor H in the new graduate nurse. The Sims Factor H Assessment Scale (SFHAS) was developed and piloted with a sample of one hundred one new graduate nurses within three months of completing the their nursing program at one of three nursing schools in central and south central Indiana. Evidence of content validity was demonstrated through the use of the Content Validity Index conducted with a panel of four experts. Evidence of face validity was demonstrated through interviews with a group of new graduate nurses, nurse managers, and experienced RN preceptors. Principle Axis Factoring with Varimax rotation was used to demonstrate evidence of construct validity and the scale was found to have a single component which was identified as nursing personality. Evidence of criterion-related validity was demonstrated utilizing analysis of the SFHAS and the criterion scale for personality traits (NEO-FFI). Evidence of internal consistency reliability was demonstrated through analysis of inter-item correlations, Cronbach’s coefficient correlations, and item-total correlations. Test re-test reliability using interclass correlation was also conducted to demonstrate stability of the scale. The SFHAS was found to be reflective of nursing personality and not general mental ability or clinical judgment. Use of the SFHAS will allow organizations to evaluate the nursing personality of the new graduate nurse for fit into the work environment. Further study is recommended to gain clarity around the attributes which support successful transition of the new graduate nurse into practice in the acute care environment, also known as Factor H.