We have gathered some examples of research questions that cannot or only with great difficulty be investigated in RCTs (table 1).
Psychometric properties of the PBMS, in particular item difficulties and variance, were investigated in a sample of 50 MS patients with relapsing-remitting disease from the MS out patient clinic at the University Medical Centre.
The effects of the difficulty parameters on Ra were investigated in several ways for different values of J: i) by introducing each parameter individually δj, j = 1,…,J, ii) by introducing their mean and variance.
More specifically, their perceived possibilities, difficulties, and support in their present and future life were investigated.
To address this difficulty, the SC's electrical properties at the cellular level were investigated.
DIF analysis were investigated to generate group-specific estimates of the item difficulty driven from IRT method using Winsteps software.
Three individuals were investigated.
The value of FEV1 as predictor of weaning difficulties has been investigated in different studies with different results.
Strategies to overcome this difficulty should be investigated in the context of neonatal intensive care.
Police have not disclosed a possible motive for the shooting but previously said they were investigating whether it was prompted by financial difficulties or other marital problems.
