A reliable and valid measurement scale
The POSAS, with high quality reliability but indeterminate validity, was considered to be superior in performance based on existing evidence.
from: A systematic review of the quality of burn scar rating scales for clinical and research use. Z. Tyack. Burns. 2012
The introduction of the Patient and Observer Scar Assessment Scale (POSAS) in 2004 was a turning point in the assessment of scars through the use of scales. The POSAS was the first scale to take into account both the patient and provider perspective, including both a Patient Scar Assessment Scale (P-SAS) and an Observer Scar Assessment Scale (O-SAS).
from: A review of scar assessment scales, Tuyet A Nguyen et al. Seminars in Cutaneous Medicine and Surgery, Vol. 34, March 2015
To date, many authors consider the POSAS most suitable for scar assessment as it includes a comprehensive list of frequently used scar features, incorporates a patients’ opinion, and has a superior internal consistency and reliability compared with the VSS..
from: a clinimetric overview of scar assessent scales, M.B.A. van der Wal et al. Journal of Burn Care and Research, 2012
The history of POSAS
“I am excited that we are now bringing together the expertise of patients and international professionals.”
‘Never create your own measurement instrument.’ That is what everyone told me at the end of the 1990s when I explored the possibility of developing a scale for assessing scars. At that time, I was halfway through my Ph.D project in which we compared the effectiveness of skin replacements in improving the quality of burn scars. Throughout this project, I was surprised by the scarcity of measuring instruments that I could use to measure the quality of scars. However, the pioneering work by Sullivan & Smith (1990) provided us with the tool that has become known as the Vancouver Scar Scale.
As is quite clear by now, I completely ignored the serious advice from the experts during my Ph.D. During the nineties, there was relatively little consideration for the opinion of patients regarding their experience, involvement and treatment outcome when seeking care. Thankfully, the world has changed! Today we acknowledge the importance of the patient opinion, which is noticeable in the development and implementation of various patient reported outcome measures. In the POSAS the patient’s opinion was included from the very beginning, as it combines the opinion of patients and observers regarding the quality of scars.
I am happy that I ignored the advice that had been giving to me regarding the development of the POSAS. I am also really proud of what we have achieved up until now. Futhermore, I am excited that we are now bringing together the expertise of patients and the input of many international professionals for the development of the POSAS version 3.0. I am looking forward to hearing about your experiences with it.
– Paul van Zuijlen, Founder of POSAS