Implementation of Problem-based Learning to Improve Critical Thinking Ability of Vocational Students in Jakarta

In the 21^st century, education must include the 4C characteristics (critical thinking, communication, collaboration, and creativity) of students. Weaknesses in the learning process and the use of inappropriate models prevent vocational school graduates from mastering these characteristics, which have a significant impact on industrial performance. This research aims to improve students’ critical thinking skills and learning outcomes after implementing problem-based learning. The research methodology used is classroom action research, which is a population study involving all TFLM 3 class students at SMKN 26 as subjects. This classroom action research involves four stages: action planning, action, observation, and reflection. Data was collected through interviews, observation, tests, and documentation. Research data in cycle I did not show an increase in critical thinking skills, with an average of 52.70% (less critical). Therefore, cycle II continued, where there was also no adequate increase in critical thinking skills, with an average of 60.38% (pretty critical). Next, cycle III was carried out, and it reached an average of 75.64% (good critical). Student learning outcomes also increased over three cycles, from 45.71% in the first cycle (low), rising to 65.71% in the second cycle (medium). Statistical analysis using the t-test shows significance. T_count = 17.598 exceeds t_table = 1.084, which indicates significant changes in critical thinking as well as significant improvements in student learning outcomes using problem-based learning. Based on the research results, it can be concluded that problem-based learning is very effective in improving critical thinking skills and learning outcomes of vocational school students.

Introduction

The urgency of the matter becomes evident when examining the results of the 2018 PISA survey, which placed Indonesia in the 74th position out of 79 participating countries (Fahlevi, 2021; Indonesia Directorate General of Primary and Secondary Education, 2022; Suryana, 2021). This ranking underscores a pressing issue: the disparity in the educational system between Indonesia and other participating countries (Fenanlampiret al., 2019). Specifically, the 2018 PISA results showed that Indonesia ranked 62^nd out of 70 countries in literacy rates (Nuret al., 2022). This poor performance in literacy can be attributed, in part, to an overemphasis on lower-order thinking skills (LOTS) in teaching, neglecting the development of higher-order thinking skills (Özer, 2020; Pratiwi, 2019). A shift to higher-order thinking skills (HOTS) is needed, which encourages critical thinking instead of rote memorization. HOTS requires students to actively engage with facts, analyzing, categorizing, manipulating, and creatively applying them to solve new problems (Hasyim & Andreina, 2019).

Critical thinking is not only essential for comprehending complex concepts but also for independent problem-solving (Gultomet al., 2021; Suyatmanet al., 2021). In the context of Indonesian students’ performance, there is room for optimism if teachers prioritize the cultivation of critical thinking skills closely linked to a deep understanding of subjects. This emphasis on critical thinking extends beyond academic realms, permeating various aspects of human life, including fields such as science, history, literature, psychology, education, and everyday situations (Berdahlet al., 2021; Jamaludinet al., 2022). The research underscores the role of critical thinking as a key predictor of academic success (Hanet al., 2020; Menapet al., 2021) because it is a calculated intelligence aspect focusing on beliefs and actions (Ennis, 2018; Menapet al., 2021). Moreover, it is a skill that is vital for lifelong learning, impacting students’ personalities and attitudes (Paidiet al., 2021). Analytical thinking, a crucial component of critical thinking, equips students with 21st-century skills needed for effective problem-solving and decision-making (Aksu & Eser, 2020; Anggrainiet al., 2019; Suyatmanet al., 2021). Therefore, teachers must instill these skills throughout lessons, where questioning, accurate information, assumptions, logical judgments, and conclusions are pivotal (Fatahet al., 2022), aligning with Indonesian students’ needs.

In the 21^st century, education must evolve to meet changing expectations (Hendi Ristantoet al., 2018). Students are expected to possess the 4C characteristics: critical thinking, creativity, communication, and collaboration (González-Salamancaet al., 2020; Ismawatiet al., 2023). These attributes are seen as essential tools for addressing societal issues and challenges effectively. However, a significant issue lies in the teaching process within classrooms, where teachers often fail to nurture students’ critical thinking skills (Alblooshi, 2021; Octavia, 2020). In typical classroom learning, the emphasis is frequently on rote memorization, neglecting the importance of understanding and applying information to real-life situations. (Deviet al., 2020) assert that while teachers demand student engagement in learning, the crucial aspects of imparting problem-solving techniques and fostering independent learning are often overlooked.

Another problem that was found based on the results of observations at school, according to Romadhon (2020), is that when learning activities, teachers still have not used appropriate learning methods for students. It can be seen from the results of their achievements that are not as expected, especially in the achievement of students’ critical thinking abilities. It turns out that there are still many teachers who apply the lecture learning method, which is a learning method that is more dominated by teachers to be more active than students (Ngadisoet al., 2021). By using this method, students feel less involved in the learning process because students just sit and listen to the teacher’s explanation and make the student passive during the learning process.

The lack of accuracy in utilizing the applied learning model within the classroom strongly suggests a connection to the diminished rate of SMK-level graduates’ readiness for the industrial sector. This data is sourced from the Central Statistics Agency (BPS) as of February 2020 (BPS (Statistics Indonesia), 2020; Surosoet al., 2021). This data reveals that the highest rate of open unemployment (TPT) is observed among SMK-level graduates, reaching 8.49%. Furthermore, the root cause of this issue lies in the inability of SMK graduates to address the challenges they encounter (Safarinahet al., 2022). During their time in school, students are not adequately accustomed to confronting problems. Triyadi (2018) contends that the production of vocational graduates competent in problem-solving necessitates adaptations in the learning process.

Having delineated some of the issues contributing to the deficiency in students’ critical thinking abilities, it becomes apparent that a solution is imperative to cultivate suitable learning approaches that cater to students’ requirements for high critical thinking skills and align with expected learning achievements. The augmentation of HOTS can be achieved through the employment of suitable pedagogical models. One such model, problem-based learning (PBL), serves as among the five teaching approaches that enable the integration of instructed content with real-world contexts, fostering student engagement (Sinabang, 2020). PBL has garnered wide-ranging endorsement and support from experts due to its proven efficacy in addressing the educational demands of the 21^st century (Bani-Hamad & Abdullah, 2019). Corebimaet al. (2020) highlight that the application of the PBL model involves real-life issues, thereby enabling students to acquire problem-solving skills pertinent to their daily lives and enhancing critical thinking abilities by incorporating crucial knowledge and concepts from the subject (Zakiaet al., 2019). Research conducted by Muktasimbillahet al. (2023) further substantiates the efficacy of the PBL model in enhancing students’ learning outcomes.

PBL is a vital teaching model within educational institutions. It was introduced by Barrows (1969) and is rooted in constructivist teaching theory. This pedagogical approach facilitates the acquisition of knowledge and skills by students via active engagement with authentic and significant situations (Yew & Goh, 2016). Placing students at its core, this approach presents real-world problems, encouraging active problem analysis, fact identification, knowledge construction, and collaborative problem-solving on a small scale, fostering improved critical thinking skills. PBL emphasizes autonomous knowledge construction, hypothesis formulation, and solution finding, nurturing independent learning and innovative spirit while also advocating for collaborative problem-solving and the development of critical thinking skills characterized by autonomy, openness, and cooperation (Gultomet al., 2021). PBL stimulates critical thinking because it facilitates students’ comprehension of concepts and subject matter. This educational encounter is also expected to foster students’ self-awareness and understanding of their surroundings, as well as their ability to identify the most conducive learning environments and circumstances (Savin-Baden, 2000).

Vocational education, especially in the context of Mechanical Engineering students, demands the application of critical thinking to solve context-specific problems. Previous studies and the principles of PBL have explained the impact on critical thinking development and students’ outcomes. While much of the existing research on the effectiveness of PBL has primarily focused on the medical field, investigating its effects in practical fields and vocational education provides valuable insights into its influence on student learning outcomes (Yew & Goh, 2016).

The proposed novelty in this study lies in the improvement of students’ critical thinking skills and learning outcomes after implementing problem-based learning in Basic Work of Mechanical Engineering Subjects for TFLM 3 class students at SMKN 26 Jakarta. By employing PBL, this study addresses the need to shift away from traditional teaching methods and towards more active and collaborative learning, ultimately enhancing students’ problem-solving abilities and overall academic outcomes. Therefore, the focus of this research is on vocational education, specifically in the field of Mechanical Engineering. The primary research inquiry centers on how students’ critical thinking skills evolve during their study of Basic Work of Mechanical Engineering Subjects through PBL at SMK 26 Jakarta.

Method

Research Design

This study used a classroom action research (CAR) method with the Kemmis and McTaggart model. This study consisted of 3 cycles, each cycle consisting of 2 meetings, and each meeting was held for 3 × 50 minutes. As per the findings of Djabbaet al. (2023), classroom action research (CAR) constitutes an investigative endeavor undertaken to assess and analyze the classroom’s student dynamics. The primary objective is to enhance and refine the quality of the instructional process, ensuring its alignment with the students’ class-specific requirements and ultimately elevating learning outcomes. In accordance with Kemmis and McTaggart (1988), the research procedure model of Kemmis and McTaggart is divided into four activity steps in each research cycle, namely (1) action planning, (2) implementation of the action, (3) observation, (4) reflection. The design of the CAR model of Kemmis and McTaggart can be seen in Fig. 1.

Fig. 1. The cycle of Kemmis and McTaggart’s action research model (Adapted from Kemmis & McTaggart, 1988).

Sample and Data Sources

This research is a population study with a sample size consisting of 35 students who are research subjects. These students are from class X TFLM 3 during the odd semester of the 2020/2021 academic year and comprise 3 female students and 32 male students. The research object is the problem-based learning method.

Procedure

The procedures in each research cycle include four stages: planning, action, observation, and reflection. In the planning stage, researchers collaborate with teachers to create lesson plans, teaching materials, learning media, PBL method syntax, and research instruments. At the action stage, the teacher carries out learning according to the plan. In PBL, there are five stages that must be carried out (Fadillaet al., 2021), including (1) student orientation towards the problem; (2) organizing students to study; (3) guiding individual groups and investigations; (4) develop and present work; and (5) analyzing and evaluating the problem-solving process, which is explained in detail in Table I. All activities related to problem-solving are recommended to be carried out both individually and in groups. The teacher’s role, in this context, primarily functions as a facilitator who provides guidance, feedback, and reinforcement when necessary. During the implementation of the action, the researcher observes the ongoing process to document its impact and collects information for the reflection stage. In the observation stage, it is used to collect activity data through observation sheets, critical thinking levels with questionnaires, and quality of learning outcomes with tests. In the reflection stage, researchers and teachers evaluate the results of observations and then reflect on plans for the next cycle. If the evaluation results have not achieved the objectives, then the reflection is on improvements to the plan that must be carried out. If the evaluation results have achieved the goal of increasing critical thinking as well as the quality of learning outcomes, then the action research is complete.

Table I. Phases of PBL Implementation

No	Phase in PBL	Behavior
1	Problem orientation	The teacher discusses the objectives of learning activities, motivates students to be involved in learning activities, and the teacher presents problems to students.
2	Learning organization	The teacher facilitates students in understanding the problems that have been presented.
3	Individual or group investigations	The teacher guides students in collecting data to get the right information and find various alternatives to solve problems.
4	Development and presentation of problem-solving results	The teacher helps students in preparing reports on the results of problem-solving.
5	Analyze and evaluate the problem-solving process	The teacher facilitates students in analyzing and evaluating the problem-solving process.

Data Collection Tools and Data Analysis Technique

The data in this study were collected using the following data collection techniques: (1) interviews, (2) observation, (3) written tests, and (4) documentation. The interview was conducted with the teacher to gather information about the condition of students in class. The purpose of these interviews was to understand the state of students in the classroom according to the subject teacher’s perspective. Observations were conducted to track the implementation of actions for students in the class, with the goal of enhancing critical thinking skills and improving student learning outcomes in each cycle. In contrast, written tests were carried out to measure students’ critical thinking levels and assess their learning outcomes after applying the PBL process.

The research instruments used in this study were (1) teacher interview sheets, (2) student activeness observation sheets, (3) observation sheets for evaluating critical thinking abilities based on aspects of the California Critical Thinking Disposition Inventory as outlined by Puet al. (2019), and (4) pretest and post-test tests. A 4-point Likert scale was used to assess the observation sheets.

The following formulae are used to analyze the percentage of student activeness, the level of student critical thinking, and student learning outcomes, respectively.

(1) $$P=\frac{n}{N}\times 100$$

Where:

P is the total percentage of student activeness,

N is the sum of obtained values,

N is the sum of all values.

(2) $$S=\frac{R}{N}\times 100$$

Where:

S is the percentage level of student critical thinking,

R is the sum of obtained scores,

N is the sum of maximum scores.

(3) $$L=\frac{NumberofstudentpassKKMScore}{Numberofstudents}\times 100$$

Where:

L is the percentage of student learning outcomes,

KKM is the minimum ability criteria.

The pretest and post-test written tests were utilized to assess the improvement in critical thinking skills and student learning outcomes, and they were analyzed using SPSS v25 with a paired sample t-test. The results of the percentage of student learning outcomes, student activity, and student critical thinking are then adjusted to the criteria achieved shown in Tables II–IV.

Table II. Criteria for Student Activity Quality

Percentage of activity (“X” Total score range)	Criteria
75% < X ≤ 100%	Very good	A
50% < X ≤ 75%	Good	B
25% < X ≤ 50%	Pretty good	C
0% < X ≤ 25%	Not good	D

Table III. Criteria for Critical Thinking Level

Score range (%)	Criteria
81–100	Very critical
66–80	Critical
56–65	Pretty critical
41–55	Less critical
0–40	Not critical

Table IV. Criteria for Student Learning Outcomes

Level of success	Information
86–100	Very high
71–85	High
56–70	Moderate
41–55	Low

In conclusion, this study employed a CAR method based on the Kemmis and McTaggart model, conducted over three cycles, with each cycle comprising two meetings held for 3 × 50 minutes. CAR serves as an investigative approach aimed at assessing and enhancing the quality of the instructional process, aligning it with students’ specific requirements, and improving learning outcomes. The procedure of this study includes action planning, action, observation, and reflection within each research cycle. The data collection tools included interviews, observations, written tests, and documentation, while data analysis encompassed calculations of student activity percentages, critical thinking percentages, and student learning outcome percentages. These findings were then compared to predefined criteria for student activity, critical thinking level, and level of success of learning outcomes, providing valuable insights into the effectiveness of the implemented PBL approach.

Results

This study focuses on the application of PBL to improve students’ critical thinking skills and student learning outcomes. The classroom action research that has been carried out consists of 3 cycles, which are carried out from November 18 to December 3. The implementation of action cycle I was carried out on November 18–19, the implementation of action cycle II was carried out on November 25–26, and the implementation of action cycle III was carried out on December 2–3.

Student Activeness Implementation with PBL

Based on Table V, the results of student activeness in cycle I amounted to 62.19% or in the good category. In the second cycle, there was an increase in student activity with a score of 71.38% or in the good category. In the third cycle, there was an increase in student activity, with a score of 79.29%, or in the very good category.

Table V. Results of Student Activeness in Cycles I, II, and III

Student activity indicators	Cycle I	Cycle II	Cycle III
Students pay attention to the teacher when giving material.	68.93	75	80.71
Students pay attention when friends present the results of the discussion.	64.29	74.26	80.71
Students ask the teacher when giving material or when friends present the results of the discussion.	61.79	69.64	78.57
Students’ express opinions when friends present the results of the discussion.	56.43	67.30	79.64
Students listen when the teacher provides material.	57.86	69.28	79.29
Students listen when friends present the results of the discussion.	60.36	68.93	76.79
Students work on assignments or questions given by the teacher.	65.71	75	79.64
Amount average (%)	62.19	71.38	79.29
Category	Good	Good	Very good

In cycle I, of the 7 indicators of student activity, none reached the completeness category. This condition was caused by the fact that the class had never applied a PBL model previously. The observations show that the lowest score for the student’s activeness indicator is found in students expressing opinions when friends present the discussion results. This is because students still look passive and afraid to express opinions, and several questions are only asked by the same student. In the first cycle, the level of completeness has not yet reached the level of completeness category, so the activeness of these students is increased again in cycle II.

In cycle II, the results of student activeness in the implementation of PBL showed a significant increase, namely with a score of 71.38%. In this cycle, there are 2 indicator points for student activeness who have reached the completeness category, namely when students pay attention to the teacher when giving material and students work on assignments or questions the teacher gives. The observations show that the lowest score for the student’s activeness indicator is still at the point where students express their opinions when friends present the discussion results. However, at this point, there was an increase in scores compared to cycle I learning, and many students began to be active in giving their opinions when friends were presenting the results of class discussions. In cycle II, this has not reached the completeness category, so the activeness of these students is increased again in cycle III.

In cycle III, all indicators of student activity have exceeded the completeness indicator. In cycle III, all students are familiar with the application of PBL and play an active role during learning.

Increasing Students’ Critical Thinking with PBL

Table VI demonstrates that, in the first cycle, the achievement of students’ critical thinking levels was 52.70% in the less critical category. In the second cycle, there was an increase in students’ critical thinking level, which was 60.38% in the quite critical category. In the third cycle, the observation results of students’ critical thinking increased back to 75.64%.

Table VI. Results of Improving Students’ Critical Thinking Cycles I, II, and III

Indicators of student critical thinking	Cycle I	Cycle II	Cycle III
Students are able to identify assumptions and reasons and recognize facts.	54.29	75.71	83.928
Students are able to present the results of the analysis.	54.29	70.71	82.499
Students are able to test the relationship of assumptions, reasons, and recognition of facts in the form of arguments.	52.14	67.86	77.499
Students’ ability to gather information from charts, diagrams, spoken language, and documents is very important.	52.50	60.36	76.428
Students are able to determine precisely the meaning of signs, data sets, written or spoken words, diagrams, icons, and graphics.	51.76	57.86	76.071
Students are able to clarify something or someone clearly.	53.57	60	75.714
Students are able to answer questions by grouping information and determining the significance of the message.	51.07	57.86	73.928
Students are able to make conclusions from reasons and evidence.	52.14	56.43	75.357
Students are able to provide suggestions and appropriate hypotheses.	52.86	57.50	74.285
Students are able to evaluate by showing a series of facts.	52.86	55.71	74.999
Students are able to evaluate by paying attention to the results of the conclusions.	52.86	56.07	74.642
Students are able to evaluate according to predetermined hypotheses.	53.57	58.93	75.356
Students are able to carry out the process of evaluating a recommendation and the right decision.	52.86	54.64	74.285
Students are able to determine the strengths and weaknesses of an argument.	53.57	60.71	75.356
Students are able to assess quality based on the results of analysis, interpretation, inference, and conclusions.	53.57	58.57	73.928
Students are able to provide strong explanations to support evaluation by providing evidence, reasons, methods, and assumptions.	53.21	58.57	72.857
Students are able to make decisions and conclusions by providing clear evidence, reasons, standards and methods.	52.86	56.79	72.927
Students are able to test, articulate reasons for beliefs, events, actions, and decisions.	51.64	60.21	76.785
Students are able to draw conclusions based on case studies, experiences	53.93	63.21	76.785
Students are able to provide a solid basis for conclusions.	50.72	60	73.22
Students are able to make correct decisions.	50.72	60.72	74.65
Students are able to determine results by seeing according to skills.	51.78	59.29	72.14
Amount average (%)	52.70	60.38	75.64
Category	Less critical	Enough critical	Critical

In cycle I, of the 22 indicators of critical thinking of the students, none of them reached the level of completeness category. This condition is because previously, the class had never applied a PBL model, and students were only required to understand the material without developing their critical thinking skills. The observations show that the lowest score for students’ critical thinking indicators is found where students can provide a strong basis for conclusions and make decisions appropriately. Students are still confused and not used to concluding when learning occurs. In the first cycle, it has not reached the completeness category, so the students’ critical thinking ability is improved again in cycle II.

In cycle II, the results of students’ critical thinking skills in implementing PBL showed an increase with a score of 60.38%. In this cycle, there is 1 point indicator of student activeness who has reached the completeness category, namely at the point where students can identify assumptions, reasons, and recognition of a fact. This has not yet reached the completeness category in cycle II, so the students’ critical thinking skills are improved again in cycle III.

In cycle III, all indicators of students’ critical thinking have exceeded completeness indicators. In cycle III, all students are familiar with the application of PBL and play an active role during learning.

Learning Outcomes of the Students with PBL

Based on Table VII, it can be seen that in cycle I the percentage of student learning outcomes completeness is at 45.71%. Whereas in cycle II the percentage of student learning outcomes completeness is at 65.71%. In the first cycle there were 16 students who had reached the KKM with a value of ≥80, while 19 other students had not reached the KKM <80. The highest score obtained by students was 85, and the lowest 65. The average score of students in Cycle II was 77.86. The percentage of completeness obtained by students in Cycle II was 65.71. The percentage of completeness has not met the predetermined success indicator of >75.

Table VII. Learning Outcomes in Cycles I and II

Completeness of student learning outcomes	Cycle I	Cycle II
The highest score	85	85
Lowest value	60	65
Average	71.57	77.86
Total students completed	16	23
Number of incomplete students	19	12
Completeness percentage (%)	45.71	65.71

The pretest and post-test scores were analyzed using a paired t-test to determine the increase in student learning outcomes. As a prerequisite for carrying out the t-test, a normality test must be carried out so that the distributed data is normally distributed. The normality test used in this study is the Shapiro-Wilk test with α of 0.05. According to Aravkar (2020) and Avram and Mărușteri (2022), if n<50 will be more accurate using the Shapiro-Wilk test, than using the Kolmogorov-Smirnov test. The results of this normality test can be seen in Table VIII.

Table VIII. Normality Test Results of the Pretest and Post-Test Data

	Kolmogorov-Smirnov			Shapiro-Wilk
	Statistic	df	Sig.	Statistics	df	Sig.
Pretest	0.237	35	<0.001	0.909	35	0.007
Post-test	0.215	35	<0.001	0.911	35	0.008

Based on the results of the Shapiro-Wilk normality test that has been carried out, the pretest and post-test data are normally distributed because p > 0.05.

Table IX shows that learning basic work of mechanical engineering by applying PBL can improve students’ critical thinking skills and student learning outcomes from an average value of 59.86 to 84.57. Table X shows a relationship between the average value. Average critical thinking and student learning outcomes before learning by applying PBL and after learning by applying PBL.

Table IX. Paired Samples Statistics

		Mean	N	Std. deviation	Std. error mean
Pair 1	Pretest	59.86	35	9.033	1.527
	Post-test	84.57	35	5.736	0.970

Table X. Paired Samples Correlations

		N	Correlation	Sig.
Pair 1	Pretest-Post-test	35	0.439	0.0008

Discussion

The utilization of PBL in the context of basic mechanical engineering has been examined in this study to augment students’ critical thinking skills and overall learning outcomes. The discussion presented here explores the importance of critical thinking skills, the role of PBL as a teaching method, the results obtained from the study, implications for education, and, ultimately, the significant contribution of PBL to enhancing critical thinking skills and learning outcomes. Critical thinking skills hold immense significance in today’s educational landscape, as they empower students to analyze, evaluate, and effectively resolve complex challenges. Students can problem-solve in a collaborative setting, create mental models for learning, and form self-directed learning habits through practice and reflection (Hmelo-Silver, 2004; Norman & Schmidt, 1992; Schmidt & Moust, 2000). Hence, the underpinning philosophy of PBL is that learning can be considered a “constructive, self-directed, collaborative and contextual” activity (Dolmanset al., 2005).In an era characterized by information overload and rapid advancements, the ability to think critically has become indispensable. These skills equip students with the capability to make well-informed decisions, tackle multifaceted problems, and adapt to ever-evolving scenarios. The pressing need for cultivating critical thinking abilities underscores the quest for innovative pedagogical approaches. PBL emerges as a transformative teaching method that fosters critical thinking skills and holistic learning. The study on the effect of PBL on developing nursing students’ critical thinking showed a positive relationship between the implementation of PBL as an instructional model and improvements in critical reasoning (Oja, 2011). Rooted in the principle of student-centered learning, PBL propels learners to actively engage with real-world issues, transcending the boundaries of traditional instruction. The collaborative nature of PBL encourages students to collaboratively identify and address intricate problems, mirroring the complexities of professional contexts. This method stimulates cognitive engagement, necessitating students to dissect information, critically analyze it, and apply their knowledge to devise solutions. Consequently, PBL catalyzes nurturing the critical thinking skills imperative for contemporary life.

The study conducted in the context of basic mechanical engineering validates the efficacy of PBL in elevating critical thinking skills and learning outcomes. The initial assessment revealed that students’ critical thinking abilities were relatively limited. However, as the cycles progressed, a substantial shift was observed, with most students transitioning to the critical thinking category. This transformation was accompanied by a remarkable rise in the average critical thinking skill score, exemplifying the potency of PBL in fostering cognitive growth. This is relevant to the study of Strobel and Van Barneveld (2009) on meta-analyses on the effectiveness of PBL, which found that PBL is more effective than traditional approaches when the measurement of learning outcomes focused on long-term knowledge retention, performance or skill-based assessment and mixed knowledge and skills. The implications of this study extend beyond its immediate scope, resonating with the broader educational landscape. In addition, as stated by Yew and Goh (2016), more rigorous research is needed to examine further the effects of PBL on student learning outcomes and performance in both academic and workplace situations. Embracing PBL can revolutionize pedagogical practices, enabling educators to cultivate multifaceted skills that transcend conventional rote learning. By immersing students in authentic problem-solving scenarios, PBL empowers them to develop the capacity to collaborate with peers, harness interdisciplinary knowledge, and apply theoretical concepts to real-world situations. The synergy between PBL and the demands of the 21^st-century education system underscores its potential to prepare students for the challenges of the modern world.

Conclusion

1. The implementation of PBL in the subject of Basic Mechanical Engineering for Grade X students in TFLM 3 at SMKN 26 Jakarta has demonstrated the potential to enhance students’ critical thinking abilities. This conclusion is supported by research findings, which indicate a notable improvement in students’ critical thinking skills.
2. The application of PBL also has shown the capacity to improve students’ academic performance in the subject of Basic Mechanical Engineering for Grade X students in TFLM 3 at SMKN 26 Jakarta. This is evidenced by a significant difference observed in both the critical thinking abilities and academic results of students before and after the implementation of PBL.