The Effectiveness of Learning Design Based on Problem Based Learning Model Oriented Mathematicalcritical Thinking Skills of Fifth Grade in Elementary School

This research is based on the low critical thinking skills shown by the low learning outcomes of students. The purpose of this study was to determine the effectiveness of learning design models based on Problem Based Learning in improving mathematical critical thinking skills of fifth-grade students in elementary schools. The research method used was quasi-experimental with a qualitative approach. The study population was all fifth-grade students of Elementary Schools in group 3 in Region II GedongTataan,Pesawaran. The research sample has 55 students and consisted of the fifth-grade student of Public Elementary School 5 GedongTataanas many as 27 students as the experimental class and the fifth-grade students of Public Elementary School 28 GedongTataanas many as 28 people as a control class. Data collection was carried out through a questionnaire and test of learning outcomes. Data analysis was performed using the acquisition of N-Gain. The results showed that the learning design based on the Problem Based Learning model was effective to improve students' mathematical critical thinking skills with the acquisition of N-Gain of 0.49.


I. INTRODUCTION
Education reform currently leads to the industrial era 4.0 and the demands of the development of the 21st century (partnership for 21 st -century skills). The National Education Association (2012:7) argues that there are 4 skills and innovations needed in the 21st century, that are critical thinking skills, creativity, collaboration skills, and communication skills.
Teachers as the spearhead of education must be able to realize learning that encourages students to engage in critical thinking. Critical thinking skills are needed by students to solve problems and make decisions in the learning process. Crawford (2005: 4)successful learningencourages students to think independently and engage in critical thinking. Germaine (2016) critical thinking means reasoning effectively, recognizing connections among systems, concepts, and disciplines to solve problems and make decisions.
Learning design designed and implemented by the teacherwill play a central role in the success of 21 st -century learning. Dick and Carey in Mudlofir (2017: 33) learning design covers the entire system approach consisting of analysis, design, development, implementation, and evaluation.
The research problem is the learning design that developed and implemented by the teacher has not yet led to a learning process that emphasizes critical thinking skills. The learning scenario tends to be a teacher center, so the teacher has not been able to develop ideas and critical ideas of students in learning. This affects the low critical thinking skills and achievement of students' mathematics learning outcomes.
The learning model that supports the development of critical thinking skills in students is Problem Based Learning. Raiyn, Jamal, &Tilchin Oleg (2015) Effective Problem Based Learning to develop High Order Thinking Skills and collaborative skills in students. Kumar, R, &Refaei, B. (2017) Students' critical thinking increases with the use of the Problem Based Learning model.This study aims to examine the effectiveness of learning design based on Problem Based Learning models oriented towards mathematical critical thinking skills in the fifth grade of Elementary School.

II. LITERATURE REVIEW 2.1 Learning Design
The purpose of learning design is that learning is conducive and meaningful for students. Sanjaya (2017: 66) learning design is a systematic process for solving learning problems through planning learning materials and activities that must be carried out, planning learning resources that can be used as well as planning evaluation of success. Hamdani (2011: 74) learning design is related to the understanding, improvement, and application of appropriate learning methods to produce the desired changes in students relating to knowledge and skills by the content of learning.
That is the design of learning about the development of the learning process that includes the formulation of Journal of Education and Practice www.iiste.org ISSN 2222-1735 (Paper) ISSN 2222-288X (Online) Vol.11, No.27, 2020 objectives to be achieved, strategies that can be implemented, and evaluation techniques to measure success.

High Order Thinking skills
The process of solving a problem requires critical thinking skills to process facts into a conclusion. Tomei in Sani (2019: 2) High Order Thinking skills include the transformation of information and ideas through the process of analyzing, synthesizing, or combining facts and ideas, generalizing, explaining, or arriving at a conclusion or interpretation. Stenberg &Lubart in Helmawati (2019: 133) High Order Thinking skills connect problem findings and creativity through planning activities, observation of problem development, and adjusting problem-solving strategies.

Problem Based Learning
Problem Based Learning is learning that optimizes students' thinking skills through a systematic group work process, students can empower, hone, test, and develop their thinking skills on an ongoing basis (Tan in Rusman, 2016: 229). Harvest in Rusmono (2014: 74) Problem Based Learning is a learning model that brings students involved in the learning process that requires them to identify problems, collect data, and use the data to solve problems. Arends in Mudlofir (2017: 74) Problem Based Learning syntax includes: (a) the orientation of students to the problem, (b) organizing students to learn, (c) guiding individual and group investigations, (d) developing and presenting the work, Dina Tsybulsky&Atar Oz (2019) applying Problem Based Learning to learning is an important step, which causes students and teachers to experience success and satisfaction, develop positive attitudes towards studentcentered learning, inquiry-based, and adopt some of the principles and aspects of Problem Based Learning pedagogy in pedagogical practice.

Critical Thinking Skills
Critical thinking is needed to make a decision from the problem faced. The ability to solve complex problems and make decisions based on complex situations is a high-level thinking skill (Halpern in Sani, 2019: 14). Conscience Suyomukti in Helmawati (2019: 104) critical thinking is a cognitive skill that allows a person to investigate a situation, problem, question, or phenomenon to make a judgment or decision.
Facione in Wang and Zheng (2016) classifies critical thinking skills including interpretation, analysis, evaluation, inference, explaining, and self-evaluation skills. The indicators of critical thinking skills developed by this study are as follows:

Indicators of Critical Thinking Skills Skill Description
Interpretation Identify or formulate a problem Analysis Examine ideas and identify arguments Inference Record the results of observations and conclude according to facts Evaluation Make and determine the results of an investigation

CHAPTER III. RESEARCH METHODS
The method or type of research used in this study is a quasi-experimental with a qualitative approach. The form of experiment used in this study was the pretest-posttest control group design. The design is described as follows:

Population
The study population was fifth-grade students in Elementary Schools in Group 3 Region II GedongTataan, Pesawaran.

Samples
The research sample is fifth-grade students of Public Elementary School 5 GedongTataantotaling 27 people as experimental class and fifth-grade students of Public Elementary School 28 GedongTataantotaling 28 people as a control class.

Data Collection Techniques a. Test Technique
In this study, the test used is an objective test by selecting multiple-choice items that are relevant to the basic competencies and indicators that have been formulated. The test consists of an initial test (pretest) and a final test (posttest).

b. Non-Test Technique
The non-test technique used in the form of an instrument consisting of; 1) Questionnaire The questionnaire in this study was intended for classroom teachers to explore data by the research problem.

2) Observation sheet
Observation sheets are used to observe the implementation of the learning process related to the activities or performance of teachers in implementing the learning design of High Order Thinking skills with the Problem Based Learning model.

3) Documentation
This technique is used to obtain the data needed by researchers such as notes, school records, and learning planning.

Data Analysis Techniques
To find out the increase in students' critical thinking skills, seen from the presence or absence of an increase in learning outcomes before and after using learning design based on Problem Based Learning model. From the data of the pretest-posttest scores obtained can be seen as an increase in learning outcomes (N-Gain). According to Hake (1999: 21), the magnitude of the increase is calculated by the normalized gain formula (normalized gain

IV. RESULTS AND DISCUSSION Results
Pretest implemented before the learning process takes place, both in the experimental class or the control class intending to measure the students' initial critical thinking skills. Posttest is held at the end of the learning process in each class, to find out whether or not there is a change/increase in students' critical thinking skills before and after using learning designs based on Problem Based Learning model. Pretest and Posttest results can be seen in the following 25.37% There is a difference in the improvement of learning outcomes based on the results of the pretest-posttest that has been done between the experimental class and the control class. The increase that occurred in the experimental class was greater when compared to the control class. This means that there is an increase in critical thinking skills in experimental class students after the learning process is implemented using a learning design based on Problem Based Learning models.
Improved learning outcomes that occur in the experimental class and control class can be seen in the following diagram: Journal of Education and Practice www.iiste.org ISSN 2222-1735 (Paper) ISSN 2222-288X (Online) Vol.11, No.27, 2020 98 The proportion of improvement in indicators of critical thinking skills in the experimental class and the control class can be seen in the following 28.89 An increase happens in every indicator of students' critical thinking skills. The skills of Interpretation, Analysis, Inference, and Evaluation of students in the Experiment class are better than the control class. This is because during the learning process with Problem Based Learning students in the experimental class are accustomed to solving problems in groups, by learning to identify problems, formulate problems, find solutions and conclude the results of problem-solving and evaluate them when presenting their work in front of the class. Improved students' critical thinking skills can be illustrated in the following bar diagram: The effectiveness test is seen based on the learning outcomes obtained after the learning process using learning designs based on the Problem Based Learning model of mathematical critical thinking skills. The following are the results of the N-Gain analysis obtained based on the results of the Pretest-Posttest conducted: No Class N-Gain 1 Experiment 0.49 2 Control 0.20 N-Gainin the experimental class is 0.49 normalized in the medium classification. That is, the level of effectiveness is in the effective category. Furthermore, the analysis carried out is to compare learning outcomes before and after learning by using a paired t-sample test (Paired t-test). Before the t-test analysis is performed, the analysis requirements test is carried out that is the data normality test. Normality testusing Kolmogorov-Smirnov The test uses the Statistical Package for the Social Sciences 25program. The results of the normality test can be Journal of Education and Practice www.iiste.org ISSN 2222-1735 (Paper) ISSN 2222-288X (Online) Vol.11, No.27, 2020 99 seen in the  -11,786 11,802 2,230 -16,362 -7,209 -5,284 27 , 000 The calculation results obtained are as follows: T-countthat obtained is -14,757 with a significance of 0,000 <0.05, then H0 is rejected and H1 is accepted. Then it can be concluded that the design of learning based on Problem Based Learning models is effective for improving mathematical critical thinking skills of fifth-grade students in elementary schools.

DISCUSSION
Learning design based on Problem Based Learning oriented critical thinking skills containing learning scenarios that focus on learning activities in solving contextual problems with systematic Problem Based Learning steps. Learning design based on Problem Based Learning is oriented towards mathematical critical thinking skills in the fifth grade of Elementary School starting with the provision of contextual problems that are close to the environment of students. Furthermore, students are facilitated to be active in groups to identify problems, formulate problems, and solve problems to be concluded so thatthey produce new knowledge. The new knowledge or new work obtained is passed on to other groups for evaluation. After learning with Problem Based Learning, students become more active in learning processes and can develop critical thinking to solve problems. This learning design, by the characteristics of learning Problem Based Learning proposed by Tan in Amir (2016: 12) Learning using Problem Based Learning begins by giving problems, learners in groups actively formulate problems and identify their knowledge gaps, learn and report solutions from the problem. The learning process that requires the habituation of students to solve and solve contextual problems makes students able to build new knowledge independently which is the result of the interaction of students with their environment. This is under the statement of Sumiati&Asra (2009: 15) which explains that learning is the process of constructing knowledge based on the experiences experienced by students as a result of their interaction with the surrounding environment.
The effectiveness of Problem Based Learning to improve students' critical thinking skills in this study, is supported by several studies that have been done before. Saputri, ArnitaCahya, et al. (2019) writing the results of the Problem Based Learning model research shows that the calculation of the average score of the acquisition of critical thinking skills in the experimental class is higher at 0.66 compared to the control class at 0.51. Research conducted by Veldez, Joseph E, Bungihan, Melfei E. (2019) to confirm the results of the study showed that: (1) the level of problem-solving skills before and after their exposure to the non-problem Based Learning approach was generally very low; (2) the level of problem-solving skills was initially very low but comparatively improved for the better after being exposed to Problem Based Learning; (3) there is a significant difference between the level of students' problem-solving skills in the Problem Based Learning group and the non-problem Based Learning approach; (4) The Problem Based Learning approach is proven to be more effective than the non-problem Based Learning approach.

V. CONCLUSION
Based on the theory and relevant research results, it can be concluded that the design of learning based on Problem Based Learning models is effective for improving students' mathematical critical thinking skills.