Abstract:
There is a clear need to harmonize outcome measurement. Some authors propose to express scores as T scores to facilitate interpretation of PROM results in clinical practice. While this is a step in the right direction, there are important limitations to the acceptance of the T score metric as a common metric when T scores are based on raw sum scores of ordinal items: Such T scores of different instruments are not exactly comparable because they are not interval scaled; T scores of different measures are only on the same scale if exactly the same reference group is used; and the T sore metric cannot be maintained because it is reference population-dependent and needs to be updated regularly. These limitations can be overcome by using an item response theory (IRT)-based metric. Items from different measures can be placed on the same IRT metric to make scores comparable on an interval scale. The PROMIS initiative used IRT to develop item banks for measuring various health outcomes. Other PROMs have been linked to the PROMIS metric. Although PROMIS uses a T-score metric for practical reasons, the underlying PROMIS metric is actually an IRT metric. An IRT approach also enables further development of an item bank while preserving the underlying metric. Therefore, IRT-based metrics should be considered as common metrics for the future.
摘要:
显然需要协调成果计量。一些作者建议将分数表示为T分数,以促进临床实践中对PROM结果的解释。虽然这是朝着正确方向迈出的一步,当T分数基于序数项目的原始总和分数时,将T分数度量作为通用度量标准存在重要限制:不同工具的此类T分数不具有完全可比性,因为它们不是间隔缩放的;如果使用完全相同的参考组,则不同度量的T分数仅在相同的量表上;并且T度量标准无法维持,因为它是参考人群依赖的,需要定期更新。这些限制可以通过使用基于项目响应理论(IRT)的度量来克服。可以将来自不同度量的项目放在相同的IRT度量上,以使分数在间隔量表上具有可比性。PROMIS计划使用IRT开发项目库,以衡量各种健康结果。其他PROM已链接到PROMIS度量。尽管出于实际原因,PROMIS使用了T分数度量,基本的PROMIS度量实际上是IRT度量。IRT方法还可以在保留基础度量的同时进一步开发项目库。因此,基于IRT的指标应被视为未来的常用指标。