Barrett, Andrew J.Murk, Peter J.2007-10-302007-10-302006-10https://hdl.handle.net/1805/1160The purpose of this research was to develop an updated scale based on the framework that Neugarten, Havighurst and Tobin (1961) used to design the Life Satisfaction Index- Form A (LSI-A). The new instrument, the Life Satisfaction Index for the Third Age LSITA), was used to assess 654 third age adults in a measurement development process to establish the LSITA’s psychometric properties. These individuals were Midwestern United States adults from selected third age learning events, retirement centers, church events, community centers and the general public. The participants were all over fifty years old consistent with the definition of the third age. The authors had been involved in a research study that used LSI-A that led to an appreciation of the importance of measuring successful aging as well as the need to apply current statistical techniques to a revised instrument. The LSITA was designed and its psychometric properties assessed using the eight-step design process from DeVellis (1991). The reliability of the 35-item scale was .93 with satisfactory content, construct and criterion validity. In addition, confirmatory factor analysis was performed using structural equation modeling and a very satisfactory goodness of fit was obtained. The new instrument has been made available to researchers by emailing ajbarret@purdue.edu. The expectation is that the researchers will provide the author with an electronic copy of their responses to add to the database.en-USAdult EducationAging (Individuals)Quantitative methodologyParticipatory ResearchParticipant SatisfactionAdult EducationArticle