The purpose of this dissertation is to identify factors that are associated with evidence-based practice (EBP) implementation. This research is an important step toward finding reasons why many EBP implementation efforts have failed. As a result, this study can provide better ways to improve EBP adoption rates. Particularly, this dissertation focuses on not only the factors themselves but also the interplay between organizational- and individual-level factors in explaining EBP implementation. This fills the gap in the existing knowledge because little research has been conducted to measure the effect of both-level characteristics. Furthermore, this dissertation aims to investigate the possible influence of the relationships between organizational- and individual-level factors on EBP implementation. This study is derived from the Global Assessment for Individual Needs (GAIN) project, which was the one-year training program for EBP implementation where the program participants (clinicians) had monthly consultations on the GAIN system. The first research question focuses on grouping the participants by considering individual and organizational factors and exploring the characteristics of these groups. In the second question, I investigate the relationships between groups identified in the first research question and the program outcomes (i.e., "utilization," "administration time," "utility insight," and "utility treatment"). The third question examines the trajectory of Evidence-Based Practice Attitudes Scales (EBPAS) over the training year. Data in this study have been collected from 37 clinicians involved in the study of GAIN implementation. Using the measures of organizational and individual factors (EBPAS and Organizational Readiness for Change (ORC)) and EBP implementation ("utilization," "administration time," "utility insight," and "utility treatment"), I conducted a series of analyses to answer these research questions. I examined how the identified factors are associated with EBP implementation in both dimensions (organizational and individual attitudes towards EBPs) by creating two corresponding composite variables (i.e., organizational- and individual-level scores) based on the standardization of the identified factors. Along with the two-different-level scores, I employed the quadrant approach (by assigning x-axis for an individual-level and y-axis for organizational-level scores) and created four groups according to the participants' coordinates in the quadrant: (1) PIPO (positive individual-level and positive organizational-level scores), (2) NIPO (negative individual-level and positive organizational-level scores), (3) NINO (negative individual-level and negative organizational-level scores), and (4) PINO (positive individual-level and negative organizational-level scores). Among these four groups, "education level" and "years in the field" are significantly different. Specifically, NINO tends to indicate higher education levels or more years in the field than the other three groups. Next, I examined the relationships between the groups and the outcomes (i.e., "utilization," "utility treatment," and "utility insight"). In utilization, particularly, PIPO shows significantly higher usages than NINO. Specifically, clinicians in PIPO administered 10 times more than those in NINO in the first month of the training. Last, I investigated the trajectory of the EBPAS to measure the effect of this project. The results show that the EBPAS scores had decreased significantly over the training year. The results of this study found that NINO shows the worst results in the outcomes--"utilization," "utility insight," and "administration time"--of the four groups. The results suggest that for successful adoption of EBP, NINO requires special attention. The small sample size is the limitation of this study, so this study had to employ special data treatment and use non-parametric analysis techniques to some degree. It is suggested that future studies collect a larger sample to detect small-to-medium effects; the larger sample size would enable researchers to employ parametric statistical analysis with various covariates. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]