Dr. Ellen Elsman is a postdoctoral research fellow with a background in epidemiology and public health. Her past and current research activities have a clear focus on the development, validation, and implementation of outcome measurement instruments, and the methodology on how to assess their quality and select the most appropriate one. During her PhD, she has developed and validated PROMs to assess the limitations in participation and activities of children and young adults with visual impairment. After her PhD, she became affiliated with the COSMIN initiative, and has focused on developing an online course on how to conduct a COSMIN systematic review of outcome measurement instruments, and conducted such a systematic review herself. Amongst other projects, she is currently leading a project in which a reporting guideline for systematic reviews of outcome measurement instruments will be developed (PRISMA-COSMIN).