There are several factors to consider in instrument development. Most patient-reported outcomes tools use Likert scales because of easier data capture and simplicity of answering. Item responses are recorded on either a Likert scale, in which several answer options are presented in a categorical fashion, or a visual analog scale, where patients mark their answer along a continuum between two ends of a spectrum ( Voutilainen et al., 2016). Initial pilot testing of proposed surveys is also performed to identify readability and redundancy of the new tool ( Sung et al., 2016). Question, or item, development ideally involves input from multiple perspectives, such as physicians, patients, epidemiologists, and psychologists and usually includes a literature review of existing tools to identify if validated surveys already exist in the space.

Instrument development is a multistep process that begins by determining what patient-reported outcomes the developers wish to measure, then generating and assembling questions into a single instrument and finally performing a psychometric analysis ( Vickery et al., 2001). That being said, these instruments require a rigorous process of development and implementation to ensure they accurately capture what the researchers intend to capture. Instruments are usually inexpensive, practical, and easy to administer. Because interviews are time and labor intensive, questionnaires (also referred to as surveys or instruments) are typically preferred. There are generally two methods for assessing patient-reported outcomes: patient-completed questionnaires and researcher-administered interviews.

Partin MD, PhD, in Campbell-Walsh-Wein Urology, 2021 Methods of Assessing Patient-Reported Outcomes

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