Why build new PROMs?
Contemporary health outcome measures have major shortcomings. Because they do not apply modern measurement theory systematically, most of these outcome measures are only moderately informative.
FIT FOR PURPOSE?
Questionnaires (profile instruments)
Generic health instruments (e.g., SF-36) lack a clear metric scale, which is required for use in evaluative medicine. Disease-specific instruments (e.g., EORTC QLQ-C30) lack the capacity to compare results across patient groups. Often very lengthy.
Preference-based instruments (conventional)
Some shortcomings of the outcome measures show up in cost-effectiveness analyses. In preference-based instruments (e.g., EQ-5D), health states are not assessed by people who are familiar with a given condition, such as patients and care-givers. Instead, members of the general population are asked to assess hypothetical disease states. Furthermore, health attributes contained in these instruments are usually selected without patient participation. Moreover, the methods (e.g., time trade-off) used by health-economists to derive values for health states are complex and known for many potential biases.