The success of the Wong-Baker FACES Pain Rating Scale has far exceeded our expectation. We have received numerous requests for the scale and for various types of information, one of them being the development of the instrument. In 1981, Donna Wong, a nurse consultant, and Connie Morain Baker, a child life specialist, were working in the burn center at Hillcrest Medical Center, Tulsa, OK. We frequently saw children who were in pain, and because of their young age, had difficulty communicating how they were feeling. Many times their complaints and cries were misunderstood by the staff, and their pain was not effectively controlled. We believed that we would be able to assess their pain better if the children were given the proper tools to communicate with.
When we reviewed the literature, we found several scales that had been used with adults and some tools that had been developed for children, such as those using colors, chips, and one unpublished paper that had used 4 different faces. We adapted a few of the adult scales and used the existing pediatric tools. During our initial attempts to find a scale that the children could use, we did not develop our ideas in terms of a research project but were primarily interested in developing a usable clinical instrument. Through experience we found that young children had considerable difficulty using any scale with a number concept, a ranking concept, or unfamiliar words. Many young children did not know colors sufficiently well to create their own color scale. However, we found that children seemed to respond well to facial expressions, and we believed that a series of faces (with numbers primarily for our own ranking purposes) would be useful for children. However, aside from the one thesis research (Alyea, 1978), we were not aware of any other work that used faces to rate pain.
Stickers were very popular during the 1980's and we often used them to reinforce cooperation during burn treatments or other phases of care. We noticed that many stickers came with facial expressions, including "smiley" faces. Connie initially began developing the faces idea by giving school-aged children 6 empty circles and having them fill in facial expressions "from a very smiling face to a very sad face" to indicate no pain to worst pain. The faces were assigned a rating from 0-5, with 0 for no pain and 1 to 5 for increasing intensities of pain. The choice of 6 faces was based on the premise that too few choices would not provide a sensitive enough rating and too many faces would be confusing to the children. Six choices were also consistent with other scales we were using and facilitated statistical comparison among the scales. We invited children, primarily those on the burn unit but also those on the general pediatric unit who had a variety of diagnoses, to help with the project of finding a way for children to tell us how much pain they had. The children readily participated and often created elaborate faces and hair styles to demonstrate the graduation from "no pain" to the "worst pain they could ever imagine." Although many children drew the sequence of no to worst pain faces from left to right, several also drew the sequence from right to left (see sample 1). We chose the left-to-right format because it was consistent with other pain scales. Over 50 children participated in the pilot work.
Although each child's series of faces was unique, we saw a pattern developing in terms of the shape of the eyes, nose, and mouth. We compiled the scales the children made and developed a composite of the most frequently drawn features. We then piloted this facial scale with a new group of over 25 children to see whether they were able to use the faces. Our preliminary results were very favorable. We then gave the same original FACES scale to a professional artist who drew the final version that is currently used. The only additional detail was more differentiation to the eyes and eyebrows.
This series of work took about 2 years to complete. Concurrently, a chronic pain program had begun at the hospital and the team physician and psychologist often worked with us on the burn unit. From their interests and the preliminary work we had done, the pain team and members of the burn staff developed a large scale research project to look at several aspects of pain in both burned adults and children. Unfortunately, the hospital was unable to financially support the study and as a result the research project was never implemented. However, we believed that the segment of the study that had been developed in terms of assessing pain in children could be continued.
Therefore, in 1983, Connie and Donna began collecting data on the validity and reliability of the faces scale we had developed, as well as an adaptation of the visual analogue scale (the glasses rating scale) and 4 other tools. Although the FACES scale was originally used in a horizontal format with happy to sad faces placed from left to right, it was reformatted in a circular fashion for the actual study. This change in format was suggested by various expert reviewers who believed that having all of the scales in a horizontal left-to-right fashion might bias the children in their selection of a pain rating. In retrospect, we do not believe that this would have occurred. Rather, the circular format confused some of the children, particularly those in the younger age group. One researcher, Roben Luffy, replicated our comparison study using most of the same scales, as well as our FACES rating scale in the original horizontal format, and found similar psychometric results.
To see if children could use the faces to distinguish between different pain intensities, Connie asked children to mark their areas of pain on a human figure drawing and then rate each area using the faces scale. Since many of these children were burned, we were aware of those areas likely to be least to most painful. The children were able to do this very accurately (see sample 2).
Most of the pilot work was done informally with children from preschool through young school age. Because teenagers could use any of the adult scales, we had few adolescent subjects in our pilot study. When we completed the data analysis of our research on the comparison of the 6 scales, we were surprised by the results, especially in terms of preference for the FACES scale by children in all of the age groups. We thought that the idea of using FACES to rate pain would seem too juvenile to the adolescents. In fact, since our research, other investigators have used the FACES scale with adults, especially the elderly, and have had successful results. Advantages of the cartoon type FACES scale is that it avoids gender, age, and racial biases.
Since we published our research, several other FACES scales have been developed, reflecting work that was concurrent with ours. We have no data on which of these scales is better or which may be preferred by different aged children. To our knowledge, our scales and those developed in Australia by Bieri and others (1990) are the only facial scales based on children's perceptions of facial expressions of no pain to worst pain. In talking with many researchers and clinicians who have tried a variety of faces scales, we have anecdotal evidence that children find our FACES very easy to use and that nurses like the convenience of a pocket-sized tool. Our research (Wong and Baker, 1988) demonstrates initial validity and reliability for the faces scale as compared to five other pain assessment instruments. Several other studies* provide additional evidence for construct validity for our scale; the studies* by Broome and others (1990) also offer evidence of discriminate validity for pain and fear. We are encouraging other clinicians and researchers to share their practice and research findings with us.
Statistical analysis for reliability using correlation coefficient.
* See other research using Wong-Baker FACES Pain Rating Scale.
Copyright, D.L. Wong and C.M. Baker, 1991.
March 15, 2002
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