International Journal of Managerial Studies and Research (IJMSR) Volume 5, Issue 9, September 2017, PP 12-17 ISSN 2349-0330 (Print) & ISSN 2349-0349 (Online) http://dx.doi.org/10.20431/2349-0349.0509003 www.arcjournals.org International Journal of Managerial Studies and Research (IJMSR) Page | 12 The Effect of Learning Strategy Training and Group Cohesiveness on Effectiveness of Decision Making Harti Supriatin 1 , Suparno Eko Widodo 2 , Rita Retnowati 3 1,2,3 Post Graduate Program, Universitas Pakuan Bogor, Indonesia 1. INTRODUCTION The success and failure of high school teachers depends on the effectiveness of a teacher's decision- making. Therefore related to the quality of education, management requires the effectiveness of a good teacher decision-making and must have leadership behaviors that can influence the learners to take an active and responsible role to achieve educational goals. Based on field observations and preliminary survey results on the effectiveness of decision making through questionnaires using a rating scale to 30 high school teachers in Bekasi City, it can be seen that some of the symptoms of poor decision making were made by some teachers. Observing some of the symptoms about poor decision making done by some teachers, it needs to get attention and need to be further investigated that is how to improve the level of success of systematic actions to solve problems in making decisions. The steps of decision range from the stage of identification and problem formulation, analyzing data and information, development and selection of alternatives, and the implementation of actions, which aim to improve the poor circumstances, in this case, the problem of learning. Based on the above explanation, the research (experiment) is done to see the problem in more detail by answering the following questions: 1. Is there any effect of decision-making effectiveness between the training group of problem-based learning strategy and the training group of learning expository learning strategy? 2. Is there any influence of decision effectiveness between training group of problem-based learning approach and a team of learning expository learning strategy that has high cohesiveness? 3. Is there any impact of decision-making effectiveness between training group of problem-based learning approach and the team of learning expository learning strategy with low cohesiveness? 4. Is there any interaction of learning strategy training and group cohesiveness to the effectiveness of decision making Abstract: The purpose of the research is to find out the influence of training method and group cohesiveness to the effectiveness of decision making. Learning strategy training and group cohesiveness serve as independent variable while decision-making effectiveness variable is the dependent variable. The sample of the research is ninety teachers chosen randomly from cluster sampling of 120 teachers from 18 private accredited A senior high schools in Bekasi city. Hypothesis testing was conducted on the level of significance 0.05. The research method used is an experiment and the technical analysis used is a two-way ANOVA. The study concludes that there is an influence between learning strategy training process of problem-based learning and expository learning into the effectiveness of decision making. There is also an impact on group cohesiveness and the efficiency of decision making, and there is influence on mutual interaction between learning strategy training method, expository learning, and group cohesiveness into the effectiveness of decision making. Keywords: Learning strategy training, problem-based learning, expository learning, cohesiveness, decision making. *Corresponding Author: Harti Supriatin, Post Graduate Program, Universitas Pakuan Bogor, Indonesia