Endpoint Outcomes is embarking on a large study to examine the selection of rating scales and response options for PRO measures from the patient’s perspective.  This research which is a mix of closed-ended exercises supplemented with qualitative interviews seeks to broaden our understanding of the best scales and response options to use in the development or PRO measures.  This ongoing work which is expected to complete in Q3 2014 is being conducted in 400 patients representing four chronic conditions. This research examines:

  • Patient preference for visual analogue scale (VAS), VAS-H, VAS-V, numeric rating scale (NRS), NRS-box plot and verbal descriptor scale (VDS)
  • Level of agreement between VAS-V, NRS, NRS-box plot and VDS
  • Whether VDSs have interval properties or are purely categorical
  • The appropriate number of categories on a VDS (none, mild, moderate and severe vs. none, very mild, moderate, severe, very severe)
  • Appropriate descriptors for VDSs
  • Preference for 24 hour recall instructions
  • Patient memory retrieval process for symptoms assessments [i.e., when patients are asked to recall the severity of a symptom do they recall the sensation of the symptom (e.g., pain intensity) or do they recall the impact of the symptom on functioning (e.g., because of pain they could not do physical activities.)