This dissertation performed an investigation of the psychometric properties of six instruments used in the 2012 Happiness Project research study. The project revisited the 2010 study conducted by Holder, Coleman, and Wallace. Holder et al. (2010) investigated the relationships among variables relating to student happiness and spirituality while attempting to control for student temperament. Instruments analyzed in this dissertation were the FACES scale (Andrews & Withey, 1976), the Oxford Happiness Questionnaire-Short Form ([OHQ-SF] Hills & Argyle, 2002), the Subjective Happiness Scales ([SHS] Lyubomirsky & Lepper, 1999a), the Spiritual Well-Being Questionnaire ([SWBQ] Gomez & Fisher, 2003), the Practices and Beliefs Scale-Behaviors ([PBS-B] Holder, Coleman, & Wallace, 2010), and the Emotionality, Activity and Sociability Temperament Survey ([EAS] Buss & Plomin, 1984). Findings suggest the PBS-B and EAS were not reasonable instruments for the sampling of late-elementary aged students (e.g., 4th, 5th, and 6th grade). Findings suggest that the OHQ-SF, SHS, and SWBQ appropriately assessed happiness and spirituality (respectively) for the sampling. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]