The specific problem addressed in this study was the low success rate of information technology (IT) projects in the U.S. Due to the abstract nature and inherent complexity of software development, IT projects are among the most complex projects encountered. Most existing schools of project management theory are based on the rational systems view; however, for projects with a high degree of complexity, a complex adaptive systems view more effectively describes the full range of project behavior. To investigate the problem, a distinction was made between project complexity and project complication. To help reduce the frequency of IT project failure, project attributes that contribute to complexity and complication were identified from literature, and a survey instrument was developed to measure and investigate relationships between IT project complication, IT project complexity, and IT project success. The survey was tested and administered to the U.S.-based membership of the Project Management Institute's Information Systems Community of Practice (PMI IS CoP). A total of 235 qualified responses were received, exceeding the minimum sample size of n = 115 determined by power analysis. The survey data was analyzed and transformed, and parametric Pearson's correlation coefficients and nonparametric Kendall's tau[subscript b] and Spearman's rho correlations were determined. Results indicated IT project complexity and IT project complication were positively correlated, but IT project complexity had a greater negative correlation with IT project success. The study expanded the application of complex adaptive systems theory to project management theory by providing empirical evidence of a distinction between project complexity and project complication, and between their respective relationships with project success. Implications for practice and future research include identifying and managing project attributes related to complexity to increase the likelihood of project success, and further investigation of project attributes related to project complexity, complication, and success. [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.]