Patient-Reported Outcomes instruments.

Elemental control of blinding.

Instrument library:
 - EQ-5D: EuroQol 5D
 - QOLS: Quality of Life Survey
 - WIQ: Walking Impairment Questionnaire
 - VAS: Visual Analog Scale for Pain Intensity
 - KCCQ: Kansas City Cardiomyopathy Questionnaire
 - IWQOL: Impact of Weight on Quality of Life
 - PSQI: Pittsburgh Sleep Quality Index
 - SF-36v2: Short Form 36v2
 -  +more