Meeting the Standards of Normal Science in Health Outcomes and Market ccess
Meeting the Standards of Normal Science in Health Outcomes and Market ccess
Meeting the Standards of Normal Science in Health Outcomes and Market Access for Pharmaceutical Products and Devices
Meeting the Standards of Normal Science in Health Outcomes and Market Access for Pharmaceutical Products and Devices

Rasch Measurement

If we are to capture change in patient response to therapy interventions, then we require a scale that meets interval or cardinal measurement properties. At the same time, if we are concerned with a meaningful measure of response then this has to be determined within disease areas. The measure must be specific to the needs of patients in the disease area.


In short, we need a measure of therapy response which meets Rasch measurement standards. This is the opposite to the claims for therapy response which characterize the overwhelming majority of patient reported outcomes instruments. They focus on physician determined measures of symptoms and response, so-called health related quality of life, rather than the needs of individual patients where their quality of life is determined by potentially more than clinically operational symptom lists.


If we are to develop appropriate measures of patient response then we should be developing patrient-centric needs fulfillment cardinal quality of life measures. To do this the instrument must meet the standards of Rasch Measurement Theory (RMT) in its development. This ensures that the instrument has the required unidimensional and interval measurement properties.


Maimon Research, through affiliates, can advise on the construction of RMT standard needs fulfillment quality of life instruments across a range of disease states. Maimon Research can also advise, if an instrument has been developed, its application to a target patient population.


Clients are advised, if they are to meet the needs of health system decision makers, to reject generic and disease specific patient reported outcomes measures unless it can be shown that they have been developed and meet RMT standards. Unfortunately few achieve these standards. Continuing to use them is inadvisable as measures of change are not mathematically defensible.


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