1. How many observers do we need for the assessment?
Draaijers et al showed in the original article that for burn scars, one observer suffices to come to a reliable Total Score of the Observer Scale. Tests revealed that one observer could reliably evaluate most separate items on linear scars, except the items ‘relief’ and ‘pliability’. For those items at least two observers were required to obtain reliable data. Evaluation by more observers will improve the reliability of the assessment obviously. However for practical reasons the number of observers should be limited to three or four.
2. I use POSAS for assessment of scars from photographs. Is that OK?
Scar evaluation by assessment from photographs is possible. However, tactile information is lacking which will hamper an optimal assessment especially for ‘pliability’. More studies are required to establish the possibilities of using photographic images of scars.
3. Should I take a training to use to POSAS?
No, that is not necessary. If you follow the instructions on this website you can use the POSAS.
Nevertheless a more extensive training module is under construction for further improvement and agreement between observers and patients that use the POSAS.
4. For what type of scars should it be used?
The POSAS is developed for all types of scars. It has been tested in linear scars, burn scars and keloid. More clinimetric studies are welcomed.
5. Can I use the POSAS Patient and Observer Scale separately?
Yes, this is possible. The scales complement each other and together they provide a more comprehensive scar assessment. The Patient Scale gives the POSAS an important extra dimension in comparison to other scar assessment scales.
6. Can patients use the Patient Scale of the POSAS at home?
Yes. When indicated patients may update their opinion without having the need to visit the hospital. This can be achieved at their convenience by internet or eMail.
7. How is the Total Score of the Observer Scale and Patient Scale calculated?
Each of the six items on both scales has a 10-point score. The Total Score of both scales can be simply calculated by adding up the scores of the six items (range 6 to 60). One may argue if the results of the separate items should be weighted to come to a more accurate Total Score. To date no convincing evidence is available to indicate that weighting improves the accuracy of the Total Score. This significance of weighting the separate items for the Total Score is currently being investigated. The Total Score of the Observer and Patient Scale altogether will give the ‘Total Score’ of the POSAS.
8. What is role of the Overall Opinion?
In addition to the six items of both the Patient and Observer Scale, both the patient and the observer gave their Overall Opinion on the appearance of the scar. Again, a 10-point scale was used in which 10 corresponded to the worst imaginable scar. The ‘Overall Opinion’ is not part of the Total Score of the POSAS. It was added to capture the general impression of a scar.
9. What is the use of the category boxes? Do I need to use them?
The category boxes were added to come to a more comprehensive evaluation of the scars. The category boxes are used for nominal data, to document the ‘direction’ of scarring (e.g. hypopigmentation or hyperpigmentation). They are not included for the Total Score.
10. I use the POSAS that was published by Draaijers et al. (POSASv1.0). Should I change to POSASv2.0?
We advocate the use of POSASv2.0 for future studies.