Secondary Logo

Share this article on:

Reply: The Limitations of Psychometric Outcome Studies in Plastic Surgery

Swanson, Eric MD

Plastic and Reconstructive Surgery – Global Open: December 2014 - Volume 2 - Issue 12 - p e279
doi: 10.1097/GOX.0000000000000250
Letters to the Editor
United States

Swanson Center, Leawood, Kans.

Correspondence to Dr. Swanson, Swanson Center, 11413 Ash Street, Leawood, KS 66211, eswanson@swansoncenter.com

This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License, where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially.

Back to Top | Article Outline

Sir:

In their response to my article,1 Panchapakesan et al2 argue that methodological standards apply to utilization (authors’ italics) of an outcome study rather than development of an outcome study. However, none of the authors’ references2 support the contention that their test development may be excused from basic considerations that lead to scientific soundness, a standard that Pusic et al3 have previously recognized as essential to validity and reliability. Panchapakesan et al2 comment that using unpublished instruments is “notoriously fraught with bias,” citing an article on schizophrenia. Ironically, the test questions and scales for the BREAST-Q and FACE-Q remain unpublished. Panchapakesan et al2 wrote that “presentation of the technical details of psychometric tests is essential to allow for critical appraisal and acceptance of a measurement instrument.” Surely such details include the test questions.

The ruler analogy2 is interesting. No one would dispute that the spaces between the numbers on a ruler must be the same. For this reason, a question on pain level, for example, would be on a different ruler than a question on nipple numbness. The BREAST-Q combines test responses into a 0–100 scale.4 What clinical meaning can be derived from this overall index? Alongside validity and reliability, Pusic et al3 previously acknowledged that a survey must be “clinical meaningful” and address “those issues considered important to patients and their surgeons.”

Panchapakesan et al2 do not recognize the fundamental difference between a survey and a test, calling the issue “just semantics,” despite the fact that this distinction is made in the psychometrics literature.5 A survey evaluates how well plastic surgeons are doing their job in providing patient satisfaction.1 A test evaluates the subject with respect to an abstract quality, such as intelligence or scholastic aptitude.5 Such tests are the proper domain of psychometrics.5

The terms of the licensing agreement do not appear in publications,4,6 but are available on the BREAST-Q Web site.7 This 11-page contract7 insists that the users not only pay a licensing fee (despite study funding from the Plastic Surgery Foundation) but also cite two specific references, insert the owners’ copyright notice on all pages presenting the BREAST-Q, withhold test questions, and provide the owners with a copy of the article for approval before submission.

Plastic surgeons are instructed to upload their patient data to the owners’ Web site for analysis and a “QScore.”8 Plastic surgeons are capable of using standard statistical tests to analyze their data; there is no need to outsource this task.1 I am not the first plastic surgeon to conclude that psychometric applications have little relevance for plastic surgeons.9 Of course, I do not take issue with psychometrics as a discipline,2 just its misapplication to plastic surgery.1 Alderman et al10 dismiss ad hoc studies but do not specifically criticize their design or methodology. The fact is, only ad hoc studies11,12 have been used successfully to compare operations.

Back to Top | Article Outline

DISCLOSURE

The author has no financial interest to declare in relation to the content of this article. The Article Processing Charge was paid for by the author.

Back to Top | Article Outline

REFERENCES

1. Swanson E. Validity, reliability, and the questionable role of psychometrics in plastic surgery. Plast Reconstr Surg Glob Open. 2014;2:e161
2. Panchapakesan V, Zhong T, Forrest CR, et al. Psychometrics: essential for valid, reliable, and responsive measurements in the development of patient-reported outcome instruments in plastic surgery. Plast Reconstr Surg Glob Open. 2014;2:e280 doi: 10.1097/GOX.0000000000000197
3. Pusic AL, Lemaine V, Klassen AF, et al. Patient-reported outcome measures in plastic surgery: use and interpretation in evidence-based medicine. Plast Reconstr Surg. 2011;127:1361–1367
4. Pusic AL, Klassen AF, Scott AM, et al. Development of a new patient-reported outcome measure for breast surgery: the BREAST-Q. Plast Reconstr Surg. 2009;124:345–353
5. Murphy KR, Davidshofer CO Psychological Testing: Principles and Applications. 20056th ed. Upper Saddle River, N.J. Pearson/Prentice Hall
6. Pusic AL, Reavey PL, Klassen AF, et al. Measuring patient outcomes in breast augmentation: introducing the BREAST-Q augmentation module. Clin Plast Surg. 2009;36:23–32
7. BREAST-Q User Agreement. Available at: https://webcore.mskcc.org/breastq/docs/bq-user-agreement.pdf. Accessed October 16, 2014
8. Score the BREAST-Q. Available at: https://webcore.mskcc.org/breastq/scoring.html. Accessed October 16, 2014
9. Hammond DC. Discussion. The BREAST-Q: further validation in independent clinical samples. Plast Reconstr Surg. 2012;129:303–304
10. Alderman AK, Bauer J, Fardo D, et al. Understanding the effect of breast augmentation on quality of life: prospective analysis using the BREAST-Q. Plast Reconstr Surg. 2014;133:787–795
11. Cruz-Korchin N, Korchin L. Vertical versus Wise pattern breast reduction: patient satisfaction, revision rates, and complications. Plast Reconstr Surg. 2003;112:1573–1578
12. Swanson E. Prospective outcome study of 106 cases of vertical mastopexy, augmentation/mastopexy, and breast reduction. J Plast Reconstr Aesthet Surg. 2013;66:937–949
© 2014 American Society of Plastic Surgeons