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Galen Research was established in 1989 as an independent research company which specializes in developing disease specific patient-reported outcome (PRO) questionnaires. The aim of Galen Research is to “improve the quality of life of patients,” and “improve the science of health measurement.” (website ref).

Since its formation in 1989, Galen has developed PRO measures which cover a range of diseases. These questionnaires include the Nottingham Health Profile (NHP), the Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) and the Rheumatoid Arthritis Quality of Life Questionnaire (RAQoL), among others. These measures have been used in studies worldwide to determine the effect a given disease has on a patient’s life.

Methodology
The development of a new PRO measure involves four stages:


 * 1) Qualitative interviews: Interviews are conducted with a variety of patients to ensure an equal representation of age, gender and disease severity. Statements are identified from these interviews which relate to the impact the condition has had on the patients’ lives. These statements are used to create a draft of the measure.
 * 2) Cognitive debriefing: The draft is tested with a new patient sample to confirm the face and content validity, relevance and comprehensiveness.
 * 3) Validation survey: The measure is tested with a validation survey with 100-200 patients, twice in a two week interval. This is used to create the final measure.
 * 4) Data analysis: The psychometric properties of the measure are assessed for test-retest reliability, internal consistency and construct validity. Analyses are performed using Item Response Theory (Rasch) analyses to ensure good scaling properties such as item fit, local item dependence, item-stability and differential item functioning according to age and gender. If the data in the scale corresponds with the Rasch model, the scale is accepted as unidimensional. This means that item scores can be added to give a total score and statistical tests can be applied to trial data.

Development of PRO measures
Galen has developed 30 PRO measures. These are: