RHINO Scale: A Question about Content Validity.

Sir:

We are writing in response to the article by Lee and Most[1] describing a new patient-reported outcome (PRO) instrument for rhinoplasty patients, that is, the RHINO Scale. This 10-item scale purports to measure satisfaction after rhinoplasty performed for functional and/or aesthetic reasons. The authors evaluated their scale in a small sample (n = 22) of patients.

We welcome the intention of surgeons taking seriously the need to capture the patient perception of outcomes of rhinoplasty. However, we are concerned that the authors do not describe any of the steps they took to develop their scale. Specifically, there is no information (nor citations pointing to other publications) about how the concepts measured by this scale were elicited. This makes its content validity, which is a core part of any new PRO instrument, at best, very difficult to judge. Content validity is the extent to which items in a PRO instrument are comprehensive and adequately measure concepts that patients consider the most important outcomes for their condition and its treatment.[2-4]

Development of a new PRO instrument involves numerous steps (Fig. 1). Concept elicitation methods used to ensure content validity include literature review, clinical expert interviews, and patient input gathered through qualitative methods (e.g., interviews and focus groups).[2-4] Patrick et al,[2] writing on behalf of the International Society for Pharmacoeconomics and Outcomes Research PRO Good Research Practices Task Force, states that qualitative data gathered as part of concept elicitation are essential for establishing the content validity of a new PRO instrument. They also state that quantitative data in a psychometric article (such as the Cronbach α and test–retest reliability findings provided by the authors in the present article), although supportive, do not document a scale’s content validity.

Fig. 1.

Three-stage approach to patient-reported outcome measure development. Reproduced from Cano SJ, Klassen A, Pusic AL. The science behind quality-of-life measurement: a primer for plastic surgeons. Plast Reconstr Surg. 2009;123:98e–106e. PROM, patient-reported outcome measurement.

In plastic surgery, measuring the patient’s perspective is highly relevant as many key outcomes, such as appearance and facial function, are best evaluated through self-report. Using qualitative methods to elicit patient stories and using these stories to develop PRO instruments represent a best practice approach to ensure content validity.[2-4] Although a PRO instrument may be shown to have excellent psychometric properties, if it fails to measure the issues that matter the most to patients, it will not be useful in clinical practice, research, or quality improvement initiatives. PRO instruments have to have content validity to be useful.

Authors of a recent literature review of PRO instruments for cosmetic surgery identified that there is a shortage of available measures.[5] As plastic surgery researchers and surgeons attend to this deficit, it is absolutely crucial that they follow best practice guidelines for PRO instrument development to avoid a proliferation of ad hoc scales.

DISCLOSURE

The authors have developed a patient-reported outcome instrument called the FACE-Q, which has a module that can be used to measure outcomes after rhinoplasty. The FACE-Q is owned by Memorial Sloan Kettering Cancer Center. As codevelopers of the FACE-Q, the authors receive a share of any license revenues as royalties based on Memorial Sloan Kettering Cancer Center’s inventor sharing policy. The Article Processing Charge was paid from a research grant.