Inter and intra-rater repeatability of the scoring of foot pain drawings

BACKGROUND Foot pain drawings (manikins) are commonly used to describe foot pain location in self-report health surveys. Respondents shade the manikin where they experience pain. The manikin is then scored via a transparent overlay that divides the drawings into areas. In large population based studies they are often scored by multiple raters. A difference in how different raters score manikins (inter-rater repeatability), or in how an individual rater scores manikins over time (intra-rater repeatability) can therefore affect data quality. This study aimed to assess inter- and intra-rater repeatability of scoring of the foot manikin. METHODS A random sample was generated of 50 respondents to a large population based survey of adults aged 50 years and older who experienced foot pain and completed a foot manikin. Manikins were initially scored by any one of six administrative staff (Rating 1). These manikins were re-scored by a second rater (Rating 2). The second rater then re-scored the manikins one week later (Rating 3). The following scores were compared: Rating 1 versus Rating 2 (inter-rater repeatability), and Rating 2 versus Rating 3 (intra-rater repeatability). A novel set of clinically relevant foot pain regions made up of one or more individual areas on the foot manikin were developed, and assessed for inter- and intra-rater repeatability. RESULTS Scoring agreement of 100% (all 50 manikins) was seen in 69% (40 out of 58) of individual areas for inter-rater scoring (range 94 to 100%), and 81% (47 out of 58) of areas for intra-rater scoring (range 96 to 100%). All areas had a kappa value of ≥0.70 for inter- and intra-rater scoring. Scoring agreement of 100% was seen in 50% (10 out of 20) of pain regions for inter-rater scoring (range 96 to 100%), and 95% (19 out of 20) of regions for intra-rater scoring (range 98 to 100%). All regions had a kappa value of >0.70 for inter- and intra-rater scoring. CONCLUSIONS Individual and multiple raters can reliably score the foot pain manikin. In addition, our proposed regions may be used to reliably classify different patterns of foot pain using the foot manikin.