Evaluating scar quality

The POSAS measures scar quality in all types of scars by evaluating visual (e.g. color), tactile (e.g. pliability) and sensory (e.g. itch) characteristics of the scar from the perspective of the observer and patients.

The first version of the POSAS has been introduced in 2004. A year later, after some minor adjustments, the second version followed. This version is available in 13 languages. Currently, the third version of the POSAS is being developed by gaining input from international scar experts (i.e. patients as well as professionals) on its content. The POSAS 3.0 is expected by July 2021.

For research and clinical use

The POSAS can be used in both clinical and research settings in order to measure the effectiveness of scar treatments, monitor scar maturation over time, and identify the need for future treatments.

From the perspective of observers and patients

Sensory characteristics can only be accurately reported by the patient, so the Observer Scale only contains those characteristics that concern the visual and tactile characteristics of the scar. Consequently, the Patient Scale contains items concerning the visual, tactile and sensory characteristics of the scar.

Learn more about these scales


The POSAS 2.0 is available in the following languages:

    • Bulgarian
    • German
    • Czech
    • Dutch
    • English
    • French
    • Hebrew (only patient scale)
    • Italian
    • Japanese
    • Norwegian
    • Romanian
    • Slovak
    • Spanish
    • Swedish

      Most of these versions have been translated by official translation offices. However, some have been translated by researchers themselves. If you are interested in translating the POSAS into your language, please contact us for permission.

      Contact us

      Development of the POSAS 3.0

      In 2017, we started the development of the POSAS 3.0. The main reasons for initiating this project was the lack of input by patients and international professionals in the development of the POSAS 2.0.

      This third POSAS version is developed to measure scar quality in patients with all types of scars, including those caused by burns, necrotizing fasciitis, acne, trauma, or surgery.

      Patient Scale

      The Patient Scale has been developed using a series of focus group meetings that took place in the Netherlands and Australia. The objective of this focus group study was to explore the concepts of scar quality that patients living with scars consider to be most important. The concepts that were identified during the focus groups determined the contents of the draft for the Patient Scale. This draft was pilot tested on patients from the Netherlands, Australia and the UK. Based on the comments made by patients, the draft was further revised.

      Observer Scale

      The Observer Scale has been developed using a systematic method to reach consensus among experts, otherwise known as a Delphi study. The POSAS 3.0 Delphi study has used three different rounds of anonymous, online questionnaires in order to obtain expert opinon on the content of the Observer Scale within the POSAS 3.0.

      Currently we are testing the measurement properties of the POSAS 3.0. We expect the POSAS 3.0 to be available by the July 2021.

      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


      Paul P.M. van Zuijlen
      Paul P.M. van ZuijlenFounder of the POSAS, Professor and Plastic, Reconstructive and Burn Surgeon
      Burn Center, Red Cross Hospital, Beverwijk, and Amsterdam UMC, location VUmc
      Michelle E. Carrière
      Michelle E. CarrièreMD, PhD candidate POSAS 3.0
      Burn Center, Red Cross Hospital, Beverwijk, and Amsterdam UMC, location VUmc
      Wieneke B. Mokkink
      Wieneke B. MokkinkSenior Researcher in Clinimetrics
      Department of Epidemiology and Biostatistics, Amsterdam UMC, location VUmc.
      Anouk Pijpe
      Anouk PijpeEpidemiologist and Research Coordinator
      Burn Center, Red Cross Hospital, Beverwijk,
      Riekie C.W. de Vet
      Riekie C.W. de VetProfessor in Clinimetrics
      Department of Epidemiology and Biostatistics, Amsterdam UMC, location VUmc.
      Frederique Kemme
      Frederique KemmeMedical student
      Burn Center, Red Cross Hospital, Beverwijk
      Françoise Loots
      Françoise LootsBackoffice and financial coordinator POSAS 3.0
      Dutch Burns Foundation, Beverwijk
      Rob Baardse
      Rob Baardse Executive Director
      Dutch Burns Foundation, Beverwijk