1. Measurement methodology in PRO research

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PROMs are the tools and/or instruments used to report PROs. Every PRO instrument contains a concept of measurement (which may be symptoms, sensation, functioning and quality of life) and way of measuring this (a rating scale of some kind).

Once the concept and the items are identified and set out, careful decisions also need to be made about:

  • how the questions are delivered to patients,
  • when the questions are delivered to patients,
  • how answers are recorded, and
  • how the data is interpreted.

 Typically, PROs are measured with questionnaires or surveys that are either:

  • completed by the patients themselves,
  • completed by the patients in the presence of the researcher,
  • completed by the researcher through face-to-face interview or by telephone interview,
  • via different interfaces such as hand-held devices or computers (see below ePROMs).

There are strengths and weaknesses to the different approaches to collecting information. For example, while the use of trained interviewers reduces errors and ensures surveys are completed, trial/treatment resources may not allow for this.It is crucial that approaches and methods used address patients’ perceptions and the actual concepts being measured rather than focusing on the interviewer and on the way questions are asked (watch out for interviewer bias). In the example given in the section above, morning symptoms can more reliably be ascertained if the questionnaire is administered in the morning than if the questionnaire is completed later during the day.