Abstract

Expanding technologies for clinical practice increase the amount of content that healthcare programs, such as Radiologic Science programs, must cover.  Educational technologies provide opportunities for new approaches to education delivery, including a shift to student-centered, active learning activities.  This literature review reveals that strategies such as questioning techniques, self-directed learning, concept mapping, problem-based learning and case-based instruction are used by educators within several allied health programs to promote active learning and encourage students to become critical thinkers and problem solvers. In cases with problem based learning curriculums, the instructor has a minimal role in student direction.  Radiologic science educators should consider how to best incorporate these active learning strategies into their teaching.

Introduction

Over the past years, the health care system has undergone rapid and unprecedented change because of a diminished life span of useful information and an increasing complexity of practice.^1,2  Specifically, many technological advantages have been made in radiologic science such as digital and computed radiography and Picture Archiving and Communication Systems (PACS). Because of the increase in the amount of information to learn in a relatively short period of time, educators have to reconsider their teaching strategies to meet the demands of a new health care system.^3,4 Educators agree lasting improvements in the health care delivery system will ultimately depend on changes in the education of those who provide the care.^5-9  Radiologic Science Educators must help students develop critical thinking skills and encourage problem-solving abilities through non-traditional methods of active learning.¹⁰  Active learning helps educators shift from a teacher-centered to a student-centered approach,⁷ which can foster independence in learning, creative problem-solving skills, a commitment to life-long learning and critical thinking.⁸

The CINAHL, Medline and Health Source: Nursing/Academic Edition databases were searched using the following key terms:  active learning, self-directed learning, teaching strategies and teaching techniques.  Only articles from peer-reviewed scholarly journals were included.  Although very little research exists on active learning in the radiologic sciences, the strategies and techniques reviewed from nursing and other healthcare areas can be applied. Most articles were published within the past five years, although older articles that had special significance to the topic were also included.  The final yield was over fifty relevant articles.

Active learning helps promote critical thinking and problem-solving abilities.^8,11-19 Characteristics of active learning include student involvement through more than just listening, emphasis on developing cognitive skills, student engagement in activities such as reading, writing and discussion, and a greater emphasis on exploration of a student’s own attitudes and values.¹⁹  Active learning means students will take greater responsibility for their own learning and become more involved in the educational process.   Active learning methods help students move away from being “spoon-fed” facts and figures to developing concepts, understanding principles and applying knowledge in clinical work.^20-21  These methods leave students with a greater level of knowledge and better learning skills.¹⁶

Lecture

Even with so many teaching strategies, the oldest and most widely used method in classroom teaching today is the lecture.^4,16  The lecture has many advantages including the ability to provide information to a large number of students,¹⁶  the ability to cover a large amount of material quickly,¹⁵  and provide cost effectiveness and efficient use of class time.²¹   The lecture is a way to introduce new material, continue discussion of a topic, and sum up course content, as well as present large blocks of complex and confusing information.²⁰  On the other hand, lectures provide less opportunity for students to process information and develop problem-solving skills, they lose students’ interest quickly and lack an opportunity to provide feedback, do not allow students to skip content they know or work at a self-directed pace and promote a teacher-centered environment instead of a student-centered environment.^18,22   Unfortunately, lecture allows students to be passive learners, depending solely on the faculty to teach them information instead of actively involving themselves in the learning process.^11,15,16,18

Questioning Strategies

Educators can use questioning strategies to develop critical thinking, decision making, and problem solving in students.²³   Because questioning techniques are a key part of active learning,¹⁷   Bloom’s taxonomy of the six levels of cognitive learning can be used to provide a framework for constructing questions.²⁴  Bloom’s taxonomy moves from the simplest level of learning (knowledge) -- to the most complex level (evaluation).  The words used to construct a question will determine the level of the answer.  For example, asking a student to define Intravenous Urogram, (IVU) would test his/her knowledge level.  Asking a student to assess a request to perform an IVU on a patient allergic to iodine, on the other hand, would test his/her evaluation level.  IVU’s are x-rays of the urinary tract. The urinary structures, including the bladder blend in with soft tissues in the abdomen; they are not easily visible on regular x-rays. To better evaluate them, iodinated contrast media must be injected into a vein. The contrast media travels through the venous system and is eventually excreted through the kidneys. At this time, radiographs of the urinary system can be obtained. Without upper level questioning, students would not be prompted to think about or use material presented.  For every question posed by an instructor, feedback is possible from the student.  According to Lozano,²⁵ “Answering questions may show the instructor that the student remembers the answer to a question or problem, but asking questions shows that students are actively thinking”.  The progression of students in the course may be evident in types of questions they ask, and a student asking questions is evidence that he or she is thinking and assimilating information.

A baccalaureate nursing program study determined what proportion of terminal objectives for clinical nursing courses are high level objectives (analysis, synthesis, evaluation), and are the kinds of questions asked by teachers and students during clinical conferences of a high level also.²⁶  Despite the fact that stated objectives specified higher cognitive-level thinking, lower-level questions comprised 98.94% of the total number of questions asked by teachers and students in the clinical conferences surveyed. 

Another study was performed within an Australian nursing program to examine clinical teachers’ use of questioning strategies.²³   The teachers’ years of classroom and clinical teaching experience, years of clinical experience, and academic qualifications were studied to see if an association between various qualifications and levels of questions existed.  Bloom’s taxonomy of the cognitive domain was used as a framework for the study.  The findings revealed clinical teachers asked more low-level questions (91.2%) than high-level questions (4.4%). 

Three Melbourne universities determined the level of questioning used by undergraduate clinical teachers and preceptors.¹⁷   Both the clinical teachers and preceptors asked a greater number of lower level questions than higher level questions. 

A Canadian baccalaureate nursing program compared the types and levels of questions asked by nurse educators and their students in context-based tutorial seminars.²⁷   The largest percentage of questions asked by educators and students were lower level.  Only 4.1% of questions asked by tutors were framed at the high-level and less than 1% of questions asked by students were rated as high-level.  These studies revealed that mainly factual and lower level questioning is being used in the classroom.

Since questioning is an integral part of teaching that can assist students in applying their knowledge,¹⁷ educators should know how to use questioning strategies effectively.  Lower level questioning does not promote critical thinking because students rely mainly on recall of information.  A simple recall of information does not enhance students’ understanding of the information in a meaningful way. Higher level questioning facilitates the development of critical thinking because it is aimed at higher cognitive levels, which involves application, analysis, synthesis and evaluation.²⁴   Educators should take advantage of stimulating questions more often to help create meaningful active learning instead of just prompting the simple recall of knowledge from students.  

Self-Directed Learning

Self-directed learning helps students take a more active role in their education and can be defined in terms of the responsibility the learner accepts for his or her own learning.^12,14,28-30  How students set learning goals, locate appropriate resources, decide on which learning methods to use and evaluate progress are all aspects of self-directed learning.³¹  Self-directed learning in the health sciences can be evident in the form of clinical logs, contracts, problem-based packages and distance learning packages.²⁹

Self-Evaluation

One form of self-directed learning is self-evaluation.  Self-evaluation allows students to assess their own performance, become more independent, and accurately identify their strengths and weaknesses within the educational environment.  Students actively setting personal goals with the instructor are a key factor in the self-evaluation process.  A study conducted in a radiography program evaluated whether student self-evaluation was a reliable and valid measure, if there were a significant difference between student self-evaluation mean scores and clinical instructor evaluation mean scores, and to what degree students expressed a favorable attitude toward self-evaluation.²⁸  Goals of the evaluation process included developing skills to identify strengths and weaknesses independently, setting goals associated with student performance and increasing student satisfaction by empowering students to control their performance.  The study was limited to this one radiologic science program, so the results may not be generalized to the radiologic science education population.  Self-evaluation was shown to be an effective method of clinical evaluation for both the students and educators in this study.  Although students tended to be slightly more critical of their performance than the instructors, a high degree of satisfaction was evident with the self-evaluation process.  Self-evaluation helps students evaluate their own performance accurately, which will be an asset in the clinical and work environments.

Learning Contracts

Learning contracts are another form of self-directed learning that encourages active learning.  According to Chien, Chan, & Morrissey,³²  “A learning contract is a written mutual agreement between teachers and students and states explicitly what a learner will do to achieve specific learning outcomes”.  Students take an increased responsibility for their own learning in academic courses and clinical education with the use of learning contracts.³³  Students set goals related to the course objectives and determine the method of measurement and evaluation criteria.^12,28,33,34   The clinical education portion of a baccalaureate radiologic science program evaluated outcomes of its contract learning experiences post graduation compared to those of two other radiologic science programs.³⁴  The study explored career satisfaction, lifelong learning skills and attitudes toward learning and learning situations.  Contracts included learning expectations, learning resources, learning experiences, documentation and other information such as designated evaluators, evaluation criteria and timelines.  Results indicated students who employed learning contracts during their course of study felt greater job satisfaction and a sense of career accomplishment, were more involved in continuing education opportunities, and had an overall positive attitude to the learning experience compared to the two other programs.

A Bachelor of Science Nursing degree program in Hong Kong undertook a study implementing contract learning in a clinical context.¹²   Results of the questionnaire survey and interviews recorded positive results including a greater sense of autonomy and control, more individualized learning, an increase in motivation and sharing in learning.  Difficulties reported while using learning contracts included an insufficient amount of time and knowledge as well as students’ learning attitudes. 

Another study introduced fieldwork educators in an occupational therapy program to learning contracts.³³  Educators felt contracts would help facilitate students’ learning and were willing to develop a fieldwork curriculum including learning contracts.  Positive attitudes were noted towards this self-directed learning experience, and learning contracts have since been part of this program.

Learning contracts were used during mental health clinical placement with baccalaureate nursing students in Hong Kong.³²  Structured activities or specifically arranged clinical situations related to their learning objectives were employed.  A questionnaire measured student perceptions and found learning contracts increased their opportunities to apply theory to practice, enhanced their motivation to learn, and promoted autonomy and control over their learning.

Concept Mapping

Concept mapping is another teaching strategy.  Mapping can promote problem solving and critical thinking by helping students process complex relationships.³⁵   Plotnick³⁶ defines a concept map as a “…graphical representation where nodes (points or vertices) represent concepts, and links (arcs or lines) represent the relationship between concepts”.  Edmondson & Smith³⁷ describe a concept map as “…a tool for representing the interrelations between concepts in an integrated, hierarchical manner”. The map provides a way to connect concepts, allowing the student to visualize during the learning process.  Many times, new meanings are constructed about events or objects based on the students’ prior knowledge.³⁸  Synthesizers, like concept maps, are graphic illustrations showing relationships among content in a general to detail or simple to complex format.³⁹  They show major relationships between ideas, and the content may be concepts, procedures or principles. 

A study was conducted to examine the effects of concept mapping and synthesizers as instructional strategies for nursing students encoding and recalling pharmacology concepts in an undergraduate pharmacology course.³⁹  Although results cannot be generalized, this study showed that using concept maps and synthesizers in the teaching environment is effective in increasing the students’ learning experience.  Another study completed by a nuclear medicine technology program used concept mapping to correct misconceptions.⁴⁰   This study demonstrated concept maps were both efficient and effective for individuals and for groups.  A veterinary program in a different study found concept maps to be instrumental in helping students’ to emphasize certain conceptual themes and interrelations.³⁷  The concept maps encouraged synthesis and integration as well as provided the course instructor with insights into common errors and misconceptions.  A nursing program in Taiwan examined the effects of adopting concept maps in problem-based learning scenario discussions.  Students were randomly assigned to a control or experimental group.  Although the program found concept mapping strategies useful for analysis of individual student’s thinking processes, there was no significant difference in student scores between the two groups within this study.³⁵      The Vee diagram is a type of concept map named because it is in the shape of a letter ‘V’.⁴¹  A nuclear medicine program study described the effects of Vee diagrams and concept maps on laboratory learning.⁴²  Diagrams were created by the students to show how their knowledge was advancing.  Instructors gave remediation and reevaluated the students’ reconstructed diagram. This study supported the use of Vee diagrams and concept maps for misconception identification and remediation. 

Problem-Based Learning (PBL)

A method of teaching using patient situations or scenarios to stimulate students to acquire and apply information to solve problems is known as problem-based learning, PBL.³⁵  In problem-based learning, problems encountered in clinical settings are presented first before students learn clinical concepts.⁴³   Educators present realistic patient scenarios, ask questions, and require students to search for holistic answers.¹⁸ Problem-based learning encourages active learning through self-directed learning, self-appraisal, development of clinical problem-solving skills and teamwork as well as requiring the student to have discipline and the integration of information.^11,44,45   PBL also improves clinical reasoning skills, increases the retention of learned material and enhances self-directed study.⁴⁶

An Australian radiation therapy program conducted a study with problem-based learning.⁴⁷   At the completion of the year, students were given a questionnaire about problem-based learning, the teaching process, assessment, and the availability of resources.  Even though results showed students felt they had become more independent learners, and the program met the aims of problem-based learning, 69.2% of the students did not feel this was an interesting learning experience.  This result was surprising but may be explained by the fact that 84.6% of students agreed with the statement, “problem-based learning is a difficult way to learn”.  Availability of resources was also a major concern with 57.7% of students probably leading to frustration.  This study highlights the importance of library resources, improving access to the resources, and increasing levels of support for the students involved in active learning. Problem-based learning is very interactive and highly involved.  It may need to be reserved for final year students who need to be challenged intellectually.⁴⁷

Another study involving problem-based learning compared test performances of chiropractic students taught by traditional methods with students using problem-based learning.¹¹   Surprisingly, no significant difference was found between the two groups.  Frustrations were noted with problem-based learning such as confusion regarding faculty-student expectations, insufficiency of faculty, student tutorials and self-directed learning strategies, and a lack of curriculum integration, learning context and provision of sufficient time to learn.

A study was conducted to determine if PBL was an appropriate learning strategy for nurses in an ambulatory care setting using ethical dilemmas as problems.⁴⁶   This teaching strategy included shared knowledge and improved decision-making and critical thinking skills as evidenced by the change in values from the pre to post- test scores.  Participants agreed, without prior knowledge of their scores, PBL is an appropriate learning strategy for ambulatory care nurses.

A Master of Nutrition and Dietetics program performed a study with problem-based learning.⁴³   Overall academic results and attitudes of students and hospital supervisors were evaluated.  Although no significant differences in final academic results were noted, this program found the content in PBL to be more relevant and in tune with contemporary practice.  Also, a reduction in the number of students requiring extra placement time to achieve competency was noted.

An occupational therapy program wanted to determine the effects of a PBL course on the development of clinical reasoning skills.⁴⁸   A quasi-experimental pretest-posttest design was used with 48 senior students.  Students participated in a PBL course scheduled prior to fieldwork.  The Self-Assessment of Clinical Reflection and Reasoning (SACRR) was administered to measure changes in clinical reasoning thought processes and behavior.  This instrument relies on the subject’s self-perception of clinical reasoning skills and behavior rather than an objective measure of clinical reasoning performance and can be a limitation of this study.  However, statistically significant improvements were seen in this PBL course, and students perceived that they increased their clinical reasoning strategies.

There are some disadvantages when considering a problem based learning curriculum. Problem-based learning is time consuming. There is concern all of the necessary and required material may not be covered.⁴⁹ Some changes to the existing curriculum will have to be made. Faculty will now have to re-evaluate the curriculum in order to develop case scenarios and create new forms of assessment.⁴⁹

Case-Based Instruction (CBI)
 

Case-based instruction (CBI) is different from PBL in which students are exposed to the content for the first time when they read the scenario.  The scenario becomes part of the explanation of the lesson in PBL.  CBI, by comparison, introduces cases after the students have completed lectures or lab units.  They apply learned theories to real-life situations.⁵⁰   Hayward & Cairns¹³ state, “The use of cases allows students to integrate and apply developing clinical and basic science knowledge and skills such as clinical reasoning, critical thinking, problem solving, and interpersonal ability to hypothetical or real case scenarios”.  Case studies provide a process of participatory learning that facilitates active and reflective learning.⁵¹

A study of physical therapy students described how they perceived and approached learning during case-based instruction.¹³   Students indicated cases served as a stimulus for clinical thinking and promoting an in-depth thought process.  Another group of physical therapy students used case studies and role-playing to learn clinical decision-making skills.⁵²   This model for teaching clinical decision-making could be incorporated into any of the health science education settings.  Allied health students were studied to see if they preferred Internet case-based instruction to didactic lecture instructional strategies in a different study.¹³   The Internet technique offered students an opportunity to apply their knowledge to solve case scenarios using a widely available technology while working collaboratively.  The respondents viewed case studies as a valuable educational experience because they were provided the opportunity to share expertise while learning from others.

Conclusion

A variety of teaching strategies can be used to provoke active learning in radiologic science students.  According to Hayward & Cairns,¹³ the goal of educators should be to “…prepare students to become competent clinicians, clinical thinkers, critical thinkers, problem-solvers and collaborators, team players, self-directed learners and effective communicators”. This applies to Radiologic Sciences as well as other healthcare fields.  Although the majority of studies within this article originate from nursing techniques, these teaching strategies can be applied to Radiologic Science as well.  Radiologic Sciences should conduct more quantitative educational research into active learning and other educational processes. More scientific studies focusing on the radiologic sciences are desperately needed to validate the successes of these teaching techniques as they would apply to our chosen field. Until that time, a Radiologic Science educator can start by identifying appropriate questioning techniques, employing self-directed learning, applying concept maps, and adding problem-based learning and case-based instruction to current teaching methods.  Active learning is essential to help radiography students and other healthcare students develop critical thinking and problem solving abilities.

References

1.    Bellack, J, Graber, D, O’Neil, E, Musham, C, Lancaster, C.   Curriculum trends in nurse practitioner programs: current and ideal. J Professional Nurs. 1999; 15:15-27.

2.  Williams, B.  Self direction in a problem based learning program.  Nurse Educ Today. 2004; 24(4): 277-285.

3.  Akinsanya, C, Williams, M.  Concept mapping for meaningful learning.  Nurse Educ Today. 2004; 24(1): 41-46.

4.  L’Eplattenier, N.  Tracing the development of critical thinking in baccalaureate nursing students.  J      N  Y State Nurses Assoc.  2001; 32(2): 27-32.

5.  Bugg, N.  Radiologic sciences educational reform: the next generation.  Radiologic Sci and Educ. 1998; 4(1): 4-10.  Available at: http://www.aers.org   Accessed November 18, 2002.

6.    Harpaz, I, Balik, C, Ehrenfeld, M.  Concept mapping: an educational strategy for advancing nursing education.  Nursing Forum.  2004; 39(2): 27-30.

7.    Hasida, B, Yagil, D, Spitzer, A.  Evaluation of an innovative curriculum:  Nursing education in the next century.  J Adv Nurs. 1999; 30(6): 1432-1441.  Available at: Epscohost database. Accessed September 4, 2002.

8.    Schaefer, K, Zygmont, D.  Analyzing the teaching style of nursing faculty.  Nurse Educ Perspect. 2003; 24(5): 238-245.

9.    Stephenson, K, Peloquin, S, Richmond, S, Hinman, M, Christiansen, C.  Changing educational paradigms to prepare allied health professionals for the 21^st century.  Educ  for Health. 2002; 15(1): 37-49.

10.  Mishoe, S.  Critical thinking in respiratory care practice: a qualitative research study.  Respir Care. 2003; 48(5): 500-516.

11.  Bovee, M, Gran, D.  Comparison of two teaching methods in a chiropractic clinical science course.  J   Allied Health.  2000; 29: 157-160.

12.  Chan, S, Wai-tong, C.  .  Implementing contract learning in a clinical context: report on a study.  J  Adv Nurs. 2000; 31(2): 298-305.

13.  Hayward, L, Cairns, M.   Physical therapist students’ perceptions of and strategic approaches to case-based instruction:  Suggestions for curriculum design.  J Physical Ther Educ.  1998; 12(2): 33-42.

14.  Hayward, L, Cairns, M.  Allied health students’ perceptions of and experiences with internet-based case study instruction.  J Allied Health. 2001; 30(4): 232-238.

15.  Hill, T.  The relationship between critical thinking and decision-making in respiratory care students.  Respiratory Care. 2002; 47(5): 571-577.

16.  Lake, D.  Student performance and perceptions of a lecture-based course compared with the same course utilizing group discussion.  Physical Ther. 2001; 81(3): 896-902.

17.  Phillips, N, Duke, M.  The questioning skills clinical teachers and preceptors:  A comparative study.    J Adv Nurs. 2001; 33(4): 523-532. Available at: Academic Search Premier database. Accessed September 12, 2002.

18. Stringer, J. Incorporation of active learning strategies into the classroom: what one person  can do.  Physician Assistant Educ.  2002; 13(2): 98-102.

19.  Vander Hoek, N.  Service-learning in radiologic science.  Radiologic Sci Educ.  2001; 6(1):
9-16.

20.  Rossignol, M.  Verbal and cognitive activities between and among students and faculty in clinical conferences.  J Nurs Educ.  2000; 39(6): 245-250.

21.  Sprawls, P. Teaching the physics of medical imaging.  Radiologic Sci Educ. 2002 ;
7(1): 8-13.

22.  Jeffries, P.  Computer versus lecture: a comparison of two methods of teaching oral medication administration in a nursing skills laboratory.  J Nurs Educ. 2001; 40(7): 323-329.

23.  Sellappah, S, Hussey, T, Blackmore, A, McMurray, A.  The use of questioning strategies by clinical teachers.  J Adv Nurs. 1998; 28(1): 142-149.

24.  Bloom, BJ.  Taxonomy of educational objectives: Cognitive and affective domains.  New York, NY: David McKay Company; 1956.

25.  Lozano, R.  Needs, practices and recommendations of active learning for today’s radiation therapy student.  Radiologic Sci Educ. 2001; 6(1): 17-28.

26.  Scholdra, J, Quiring, J.  The level of questions posed by nursing educators.  J Nurs Educ. 1973; 12(3): 15-20.

27.  Profetto-McGrath, J, Smith, K, Day, R, Yonge, O.  The questioning skills of tutors and students in a context based baccalaureate nursing program.  Nurse Educ Today.  2004; 24(5): 363-372.

28.  Carwile, L, Murrell, J.  Student self-evaluation in clinical education.  Radiologic Technol. 2002; 73: 415-423.  Available at: http://galenet.galegroup.com  Accessed November 6, 2002.

29.  Fisher, M, King, J, Tague, G.  Development of a self-directed learning readiness scale for nursing education.  Nurse Educ Today. 2001; 21: 516-525.

30.  O’Shea, E.  Self-directed learning in nurse education:  a review of the literature.  J Adv Nurs. 2003; 43(1): 62-70.

31.  Alexander, S, Kernohan, G, McCullagh, P.  Self directed and lifelong learning.  Studies in Health Technol  Inf.  2004; 109: 152-66.

32.  Chien, W, Chan, S, Morrissey, J.  The use of learning contracts in mental health nursing clinical placement: an action research.  Int J Nurs Stud. 2002; 39(7): 685-694.

33.  Tsang, H, Paterson, M, Packer, T.  Self-directed learning in fieldwork education with learning contracts.  Br J Ther Rehabil.  2002; 9(5): 184-189.

34.  Renner, J, Stritter, F, Wong, H.  Learning contracts in clinical education.  Radiologic Technol. 1993; 64(6): 358-365.

35.  Hsu, L.  Developing concept maps from problem-based learning scenario discussions. 
J Adv Nurs. 2004; 48(5): 510-518.

36.  Plotnick, E.  A graphical system for understanding the relationship between concepts.  Teacher Librarian. 2001; 28(4): 42-45.

37.  Edmondson, K, Smith, D.  Concept mapping to facilitate veterinary students’ understanding of fluid and electrolyte disorders.  Teaching and Learning in Med. 1998; 10(1): 21-33.

38.All, A, Huycke, L, Fisher, M.  Instructional tools for nursing education:  concept maps.  Nurs Educ Perspect. 2003; 24(6): 311-317.

39.  Gaines, C.   Concept mapping and synthesizers: Instructional strategies for encoding and recalling.  J N Y State Nurses Assoc. 1996; 27(1): 14-18.

40.  Passmore, G.  Constructing concept maps facilitates learning in radiologic technologies education.  Radiologic Sci Educ. 1995; 2(2): 50-59., Available at: http://www.aers.org   Accessed November 18, 2002.

41.  Andersen, G.  What is research?  n.d.  Available at:  http://kancrn.kckps.k12.ks.us/guide/research.html Accessed November 19, 2003.

42.  Passmore, G.  Using Vee diagrams to facilitate meaningful learning and misconception remediation in radiologic technologies laboratory education.  Radiologic Sci Educ. 1998; 4(1), 11-28.  Available at: http://www.aers.org   Accessed November 18, 2002.

43.  Winter, J, Matters, H, Nowson, C.  A problem-based approach to clinical education in dietetics.  Nutr Diet. 2002; 59(1): 23-28.

44.  Kamin, C, O’Sullivan, P, Younger, M. Deterding, R.  Measuring critical thinking in problem-based learning discourse.  Teaching Learning Med. 2001; 13(1): 27-35.

45. Whitfield, C, Mauger, E, Zwicker, J, Lehman, E.  Differences between opportunities students in problem-based and lecture-based curricula measured by clerkship performance ratings at the beginning of the third year.  Teaching and Learning  Med. 2002;14(4): 211-217.

46.  Williams, R, Sewell, D, Humphrey, E.   Implementing problem-based learning in ambulatory care.  Nurs Econ. 2002; 20(3): 135-141.

47.  Cox, J, Rinks, M.  Early experiences with problem-based learning in a radiation therapy program.  Radiologic Sci Educ. 1996; 3(1): 24-30.  Available at: http://www.aers.org  Accessed November 18, 2002.

48.  Scaffa, M, Wooster, D.  .  Effects of problem-based learning on clinical reasoning in occupational therapy.  Am J Occup Ther. 2004; 58(3): 333-336.

49.  Kowalczyk, N, Leggett, TD.  Teaching critical-thinking skills through group-based learning. Radiologic Tech. 2005; 77(1): 24-31.

50.  DeMarco, R, Hayward, L, Lynch, M.  Nursing students’ experiences with and strategic approaches to case-based instruction: a replication and comparison study between two disciplines.  J Nurs Educ. 2002; 41(4): 165-173.

51.  Tomey, A.  Learning with cases.  J Continuing Educ Nurs. 2003; 34(1): 34-38.

52.  Leighton, R, Sheldon, M.  .Model for teaching clinical decision making in a physical therapy professional curriculum.  J Phys Educ. 1997; 11(2): 23-30.