It is important that school employees understand the meaning of Harassment, Intimidation, and Bullying [HIB] as defined by NJ's HIB legislation as a result of the professional development [PD] opportunities provided by their school district. Adequate training on HIB, HIB legislation, and intervention/prevention strategies is paramount in reducing bullying rates everywhere. Despite HIB legislation, bullying is still a pervasive problem nationally and internationally. This study aimed to determine the efficacy of HIB PD provided by four New Jersey school districts and deduce whether or not their 342 middle and high school personnel could correctly identify, prevent, investigate, respond to, and report HIB incidents. This mixed method longitudinal study synthesized ex post facto data (i.e. number of HIB investigations, number of confirmed HIB acts, and School Self-Assessment scores) collected from all four participating New Jersey school districts from 2010 to 2016. Survey data were also obtained from a total of 229 respondents to determine how the middle and high school personnel perceived the value of the 2015-2016 HIB PD in curbing bullying behavior. The original, web-based, multiple-response survey included Bauman, Rigby, and Hoppa's (2008) "Handling Bullying Questionnaire [HBQ]." It was tailored to 17 different roles. Both middle and high school respondents had 5 weeks to complete the multiple-choice, 5 point-Likert scales, closed and open-ended survey items. Research findings on the four participating New Jersey school districts were: school employees were primarily not asked their opinion about the implemented HIB programs and/or interventions, there was little to no measurement of their HIB program's efficacy, and the annual HIB PD was primarily isolated, impersonal, and task-driven. Personnel gave mixed responses about whether an assessment was provided following their HIB PD. [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.]