Learning the ‘‘learning curve’’ Philippe Grange, MDa,b,c and Mubashir Mulla, MRCS, MMED,a,d London and Wales, UK, and Hamburg, Germany
From the King’s College Hospital,a Kings Health Partners; Kings Learning Institute,b Kings College London, London, UK; Universit€ a tsklinikum Hamburg-Eppendorf,c Hamburg, Germany; and Ysbyty Gwynedd,d Bangor, Wales, UK
THE USE OF THE WORD ‘‘STEEP’’ in relation to a learning curve can lead to confusion. The ‘‘learning curve’’ was first described by Ebbinghaus,1 a psychologist and mathematician, in his study on memorization. On the initial shallow part of this curve, little is memorized at each trial; whereas on the intermediate steep leg, significantly more is learned over a shorter period and then, on the final asymptote, once again progress is slow. Hence, the steeper the curve, the easier and quicker is the learning process. This scientific representation conflicts with the imagery of the word ‘‘steep,’’ climbing an obstacle for instance. To clarify this, we explored what various authors have meant by ‘‘steepness’’ in the 200 laparoscopic/robotic papers written about learning curves during a 9-month period in 2013. We found that 84% interpreted steep incorrectly as ‘‘difficult,’’ whereas the remaining 16% correctly identified steep as ‘‘ease of learning.’’ This inconsistent interpretation of the word steep is problematic: the different uses of this word are not precise when dealing with important topics, such as the development and refinement of surgical techniques. Further confusion arises from descending learning curves, such as to represent decreasing operative times, much like manufacturers do for reporting training costs.2 With this in mind, the choice of measurable criteria in surgery is of paramount importance: outcomes-related and patientcentered criteria, such as recurrence-free rates are preferable to simply decreased operative
Accepted for publication July 17, 2014. Reprint requests: Mubashir Mulla, MRCS, MMED, Department of Surgery, Ysbyty Gwynedd, Bangor, Gwynedd LL57 2PW, Wales, UK. E-mail: [email protected]. Surgery 2015;157:8-9. 0039-6060/$ - see front matter Ó 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.surg.2014.07.017
8 SURGERY
Fig. The interplay between Dreyfus and Dreyfus’ stages of skills acquisition and Ebbinghaus’ learning curve.
times.3 There are more lessons to be extracted from the learning curve. By mapping the staged model of skills acquisition by Dreyfus and Dreyfus4 onto the learning curve, we can illustrate the progress of trainees from novice to advanced-beginner, competent, proficient, and then expert (Fig). The majority of authors focus on the highly predictable right part of the curve, which illustrates transition from early competencies to full proficiency; better and faster execution is correlated with the amount and regularity of practice. The development of automatisms and economy of movements results in a subsequent fluid performance.5 As educators, our priority should be to focus on the initial part of the curve, which represents progress from the novice level to the competent level, where there is increased risk for patient safety and difficulty for the trainee. Furthermore, by shifting the curve to the left, we could address some of the issues of regulated working hours. In conclusion, to convey precisely the difficulty and length of climbing or descending the learning curve, we suggest avoiding the word ‘‘steep.’’
Surgery Volume 157, Number 1
REFERENCES 1. Wozniak RH. Introduction to memory: Hermann Ebbinghaus (1885/1913). In: Classics in psychology, 1855-1914: Historical Essays. Bristol, UK: Thoemmes Press; 1999. 2. Wright TP. Factors affecting the cost of airplanes. J Aeron Sci 1936;3:122-8. 3. Vickers AJ, Savage CJ, Hruza M, Tuerk I, Koenig P, MartınezPi~ neiro L, et al. The surgical learning curve for laparoscopic
Grange and Mulla 9
radical prostatectomy: a retrospective cohort study. Lancet Oncol 2009;10:475-80. 4. Dreyfus HI, Dreyfus SE. Mind over machine, the power of human intuition and expertise in the era of the computer. New York: Free Press; 1988. 5. Bloom BS. Automaticity: the hand and feet of a genius. Educ Leadership 1986;46:70-7.
From the King’s College Hospital,a Kings Health Partners; Kings Learning Institute,b Kings College London, London, UK; Universit€ a tsklinikum Hamburg-Eppendorf,c Hamburg, Germany; and Ysbyty Gwynedd,d Bangor, Wales, UK
THE USE OF THE WORD ‘‘STEEP’’ in relation to a learning curve can lead to confusion. The ‘‘learning curve’’ was first described by Ebbinghaus,1 a psychologist and mathematician, in his study on memorization. On the initial shallow part of this curve, little is memorized at each trial; whereas on the intermediate steep leg, significantly more is learned over a shorter period and then, on the final asymptote, once again progress is slow. Hence, the steeper the curve, the easier and quicker is the learning process. This scientific representation conflicts with the imagery of the word ‘‘steep,’’ climbing an obstacle for instance. To clarify this, we explored what various authors have meant by ‘‘steepness’’ in the 200 laparoscopic/robotic papers written about learning curves during a 9-month period in 2013. We found that 84% interpreted steep incorrectly as ‘‘difficult,’’ whereas the remaining 16% correctly identified steep as ‘‘ease of learning.’’ This inconsistent interpretation of the word steep is problematic: the different uses of this word are not precise when dealing with important topics, such as the development and refinement of surgical techniques. Further confusion arises from descending learning curves, such as to represent decreasing operative times, much like manufacturers do for reporting training costs.2 With this in mind, the choice of measurable criteria in surgery is of paramount importance: outcomes-related and patientcentered criteria, such as recurrence-free rates are preferable to simply decreased operative
Accepted for publication July 17, 2014. Reprint requests: Mubashir Mulla, MRCS, MMED, Department of Surgery, Ysbyty Gwynedd, Bangor, Gwynedd LL57 2PW, Wales, UK. E-mail: [email protected]. Surgery 2015;157:8-9. 0039-6060/$ - see front matter Ó 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.surg.2014.07.017
8 SURGERY
Fig. The interplay between Dreyfus and Dreyfus’ stages of skills acquisition and Ebbinghaus’ learning curve.
times.3 There are more lessons to be extracted from the learning curve. By mapping the staged model of skills acquisition by Dreyfus and Dreyfus4 onto the learning curve, we can illustrate the progress of trainees from novice to advanced-beginner, competent, proficient, and then expert (Fig). The majority of authors focus on the highly predictable right part of the curve, which illustrates transition from early competencies to full proficiency; better and faster execution is correlated with the amount and regularity of practice. The development of automatisms and economy of movements results in a subsequent fluid performance.5 As educators, our priority should be to focus on the initial part of the curve, which represents progress from the novice level to the competent level, where there is increased risk for patient safety and difficulty for the trainee. Furthermore, by shifting the curve to the left, we could address some of the issues of regulated working hours. In conclusion, to convey precisely the difficulty and length of climbing or descending the learning curve, we suggest avoiding the word ‘‘steep.’’
Surgery Volume 157, Number 1
REFERENCES 1. Wozniak RH. Introduction to memory: Hermann Ebbinghaus (1885/1913). In: Classics in psychology, 1855-1914: Historical Essays. Bristol, UK: Thoemmes Press; 1999. 2. Wright TP. Factors affecting the cost of airplanes. J Aeron Sci 1936;3:122-8. 3. Vickers AJ, Savage CJ, Hruza M, Tuerk I, Koenig P, MartınezPi~ neiro L, et al. The surgical learning curve for laparoscopic
Grange and Mulla 9
radical prostatectomy: a retrospective cohort study. Lancet Oncol 2009;10:475-80. 4. Dreyfus HI, Dreyfus SE. Mind over machine, the power of human intuition and expertise in the era of the computer. New York: Free Press; 1988. 5. Bloom BS. Automaticity: the hand and feet of a genius. Educ Leadership 1986;46:70-7.
